U.S. patent application number 17/238044 was filed with the patent office on 2021-09-09 for fluid-cooled led-based lighting methods and apparatus in close proximity grow systems for controlled environment horticulture.
This patent application is currently assigned to Agnetix, Inc.. The applicant listed for this patent is Ihor Lys, Nicholas Maderas. Invention is credited to Ihor Lys, Nicholas Maderas.
Application Number | 20210278072 17/238044 |
Document ID | / |
Family ID | 1000005626840 |
Filed Date | 2021-09-09 |
United States Patent
Application |
20210278072 |
Kind Code |
A1 |
Lys; Ihor ; et al. |
September 9, 2021 |
FLUID-COOLED LED-BASED LIGHTING METHODS AND APPARATUS IN CLOSE
PROXIMITY GROW SYSTEMS FOR CONTROLLED ENVIRONMENT HORTICULTURE
Abstract
A lighting fixture includes a frame, one or more LED light
sources to emit radiation, control circuitry to receive AC power
and control the one or more LED light sources, and a coolant pipe
to carry a fluid coolant. The lighting fixture further includes a
tube and end caps that together form an enclosed cavity to contain
the frame, the LED light sources, and the control circuitry. In
example implementations, the tube does not physically contact the
frame, the LED light sources, and the control circuitry. The cavity
may further contain air, gas, or vacuum that forms a thermal
barrier between the tube and the LED light sources to reduce heat
dissipation from the LED light sources to the environment. The tube
may further enable the lighting fixture to be rotatably and/or
translationally adjustable relative to a support structure after
installation in a close proximity grow system.
Inventors: |
Lys; Ihor; (La Jolla,
CA) ; Maderas; Nicholas; (Richmond, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lys; Ihor
Maderas; Nicholas |
La Jolla
Richmond |
CA
CA |
US
US |
|
|
Assignee: |
Agnetix, Inc.
San Diego
CA
|
Family ID: |
1000005626840 |
Appl. No.: |
17/238044 |
Filed: |
April 22, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/US2020/064837 |
Dec 14, 2020 |
|
|
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17238044 |
|
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62947538 |
Dec 12, 2019 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A01G 9/249 20190501;
F21Y 2115/10 20160801; F21S 4/28 20160101; F21Y 2103/10 20160801;
F21V 29/503 20150115; F21W 2131/109 20130101; F21V 29/51 20150115;
F21Y 2113/13 20160801 |
International
Class: |
F21V 29/51 20060101
F21V029/51; F21V 29/503 20060101 F21V029/503; F21S 4/28 20060101
F21S004/28; A01G 9/24 20060101 A01G009/24 |
Claims
1. A fluid-cooled LED-based lighting fixture for an agricultural
environment, the lighting fixture comprising: a frame having a
coolant channel; at least one LED light source, coupled to the
frame, to emit radiation; control circuitry, coupled to the frame
and electrically coupled to the at least one LED light source, to
receive AC power and to control the at least one LED light source;
a tube defining a cavity with a first open end and a second open
end, the cavity containing the frame, the at least one LED light
source, and the control circuitry, the tube being transparent to
the radiation; a first end cap disposed at the first open end of
the tube and coupled to the frame; a second end cap disposed at the
second open end of the tube and coupled to the frame, the first and
second end caps enclosing the cavity of the tube; and a coolant
pipe, at least partially disposed in and thermally coupled to the
coolant channel of the frame, to carry a fluid coolant that
extracts heat generated by the at least one LED light source during
operation of the lighting fixture, the coolant pipe passing through
a first fluidic feedthrough in the first end cap and a second
fluidic feedthrough in the second end cap.
2. The lighting fixture of claim 1, wherein the tube has a
cross-sectional shape, in a plane parallel to the first and second
open ends of the tube, that is at least one of a circle, a
semi-circle, an ellipse, or a polygon.
3. The lighting fixture of claim 2, wherein: the cross-sectional
shape of the tube is a circle; and when the lighting fixture is
deployed in the agricultural environment and coupled to a support
structure, the lighting fixture is at least one of rotatably
adjustable or translationally adjustable with respect to the
support structure such that the radiation emitted by the at least
one LED light source is redirected onto different portions of the
agricultural environment when the lighting fixture is moved with
respect to the support structure.
4. The lighting fixture of claim 3, wherein the lighting fixture is
rotatably adjustable with respect to the support structure about a
longitudinal axis of the tube.
5. The lighting fixture of claim 3, wherein the lighting fixture is
coupled to the support structure via at least one of a pin joint or
a slider joint.
6. The lighting fixture of claim 1, wherein the tube has an
exterior width of about 2 inches.
7. The lighting fixture of claim 6, wherein the tube has an
exterior length of about 48 inches or about 96 inches.
8. The lighting fixture of claim 1, wherein the tube is formed from
at least one of glass, polycarbonate, acrylic, or
polymethylmethacrylate (PMMA).
9. The lighting fixture of claim 1, wherein the tube has a
transmittance greater than or equal to 80% for ultraviolet
radiation having wavelengths ranging between 170 nm and 400 nm.
10. The lighting fixture of claim 1, wherein the frame is coupled
to the first and second end caps such that the tube does not
physically contact the frame, the at least one LED light source,
the control circuitry, and the coolant pipe.
11. The lighting fixture of claim 10, wherein: the cavity of the
tube further contains at least one of air, gas, or vacuum; and the
air, gas, or vacuum separating the tube from the frame, the at
least one LED light source, the control circuitry, and the coolant
pipe forms a thermal barrier that reduces transfer of the heat
generated by the at least one LED light source during operation of
the lighting fixture to the agricultural environment.
12. The lighting fixture of claim 1, wherein: the frame thermally
expands due to the heat generated by the at least one LED light
source during operation of the lighting fixture such that a first
length of the frame changes relative to a second length of the
tube; and the first and second end caps deform in response to the
relative change in the first and second lengths so as to remain
coupled to the frame and the tube.
13. The lighting fixture of claim 1, wherein the cavity is
sufficiently sealed such that water does not infiltrate into the
cavity when water washes over the lighting fixture.
14. The lighting fixture of claim 13, wherein water does not
infiltrate into the cavity when the lighting fixture is submerged
in water.
15. The lighting fixture of claim 1, wherein: the first end cap
comprises: an end cap cover having a first sidewall that defines a
first cavity to receive the tube and the frame; and an end cap
support, disposed within the first cavity of the end cap cover and
coupled to the frame, having a second sidewall that is
concentrically aligned with the first sidewall such that the first
and second sidewalls form a clamp to couple the first end cap to
the tube; and the tube is disposed between the first and second
sidewalls.
16. The lighting fixture of claim 15, wherein the end cap cover is
formed from at least one of rubber, urethane, or silicone.
17. The lighting fixture of claim 15, wherein the end cap support
is formed from at least one of glass-filled polycarbonate.
18. The lighting fixture of claim 1, wherein the frame further
comprises: a first frame component having a first side that couples
to the at least one LED light source and a second side opposite the
first side; and a second frame component, coupled to the second
side of the first frame component, to couple to the control
circuitry.
19. The lighting fixture of claim 18, wherein: the coolant channel
is formed on the second side of the first frame component such that
the coolant channel is disposed between the at least one LED light
source and the control circuitry; and the coolant pipe extracts the
heat generated by the at least one LED light source during
operation of the lighting fixture via heat conduction through the
first frame component.
20. The lighting fixture of claim 18, wherein the first frame
component is formed from aluminum.
21. The lighting fixture of claim 18, wherein the second frame
component electrically isolates the control circuitry from the
first frame component.
22. The lighting fixture of claim 18, wherein the second frame
component is formed from plastic.
23. The lighting fixture of claim 18, wherein the first frame
component further comprises: a first mounting channel, formed on
the first side, to slidably receive the at least one LED light
source; and a second mounting channel, formed on the second side,
to slidably receive the second frame component.
24. The lighting fixture of claim 18, wherein: the tube has an
exterior length; the first frame component spans the exterior
length of the tube; and the second frame component spans a portion
of the length of the tube.
25. The lighting fixture of claim 1, wherein the coolant pipe is
formed from copper.
26. The lighting fixture of claim 25, wherein the coolant pipe is
coated with nickel.
27. The lighting fixture of claim 1, wherein the coolant pipe has
an exterior width less than or equal to about 0.5 inches.
28. The lighting fixture of claim 1, wherein the coolant pipe is
press fit into the channel of the frame.
29. The lighting fixture of claim 1, wherein: the at least one LED
light source comprises a plurality of LED light sources to emit the
radiation; and the radiation includes one or more wavelengths or
wavelength bands.
30. The lighting fixture of claim 29, wherein the plurality of LED
light sources comprises at least one of: a red LED to emit red
light; a white LED to emit white light; or a blue LED to emit blue
light.
31. The lighting fixture of claim 30, wherein the radiation emitted
by the red LED, the white LED, and the blue LED is independently
adjustable via the control circuitry.
32. The lighting fixture of claim 1, wherein the at least one LED
light source comprises: a first LED light source having a first
field of view and emitting first radiation within the first field
of view to illuminate the agricultural environment; and a second
LED light source having a second field of view that does not
overlap the first field of view and emitting second radiation
within the second field of view to illuminate the agricultural
environment.
33. The lighting fixture of claim 32, wherein a first optical axis
of the first field of view and a second optical axis of the second
field of view are oriented in opposing directions such that the
first and second radiation provides interlighting of the
agricultural environment.
34. The lighting fixture of claim 32, wherein the first and second
fields of view are hemispherical in shape such that the first and
second radiation provides omni-directional illumination of the
agricultural environment.
35. The lighting fixture of claim 1, wherein: the AC power is
greater than or equal to about 175 W; and the tube has an exterior
width of about 2 inches and an exterior length of about 96
inches.
36. The lighting fixture of claim 1, wherein: the AC power is
greater than or equal to about 175 W; and the lighting fixture
illuminates a portion of the agricultural environment having a
volume of about 35 cubic feet.
37. The lighting fixture of claim 1, wherein: the at least one LED
light source emits the radiation at a nominal intensity; and the
control circuitry includes a dimmer to controllably reduce the
radiation down to about 1% of the nominal intensity.
38. The lighting fixture of claim 1, further comprising: an alert
indicator, electrically coupled to the control circuitry and
disposed on an exterior surface of the frame that is perceivable by
a user when the lighting fixture is installed in an agricultural
environment, to provide at least one of a visual or audio alert
when the lighting fixture meets a condition.
39. The lighting fixture of claim 38, wherein the condition is met
when the lighting fixture overheats.
40. A fluid-cooled LED-based lighting fixture, comprising: a frame,
comprising: a first frame component having a first side and a
second side, opposite the first side, having a coolant channel
formed therein; and a second frame component coupled to the second
side of the first frame component; at least one LED light source,
coupled to the first frame component, to emit radiation; control
circuitry, coupled to the second frame component and electrically
coupled to the at least one LED light source, to receive AC power
and to control the at least one LED light source; and a coolant
pipe, at least partially disposed in and thermally coupled to the
coolant channel of the first frame component, to carry a fluid
coolant that extracts heat generated by the at least one LED light
source, wherein: the first frame component thermally conducts the
heat generated by the at least one LED light source to the coolant
pipe; and the second frame component electrically isolates the
control circuitry from the first frame component.
41. The lighting fixture of claim 40, wherein: the first frame
component has a first length; and the second frame component has a
second length less than the first length.
42. The lighting fixture of claim 40, further comprising: a tube
defining a cavity with a first open end and a second open end, the
cavity containing the frame, the at least one LED light source, the
control circuitry, and at least a portion of the coolant pipe, the
tube being transparent to the radiation; a first end cap disposed
at the first open end of the tube and coupled to the frame, the
first end cap having a first fluidic feedthrough through which the
coolant pipe passes through; and a second end cap disposed at the
second open end of the tube and coupled to the frame, the second
end cap having a second fluidic feedthrough through which the
coolant pipe passes through, the first and second end caps
enclosing the cavity of the tube.
43. The lighting fixture of claim 42, wherein the frame is coupled
to the first and second end caps such that the tube does not
physically contact the frame, the at least one LED light source,
the control circuitry, and the coolant pipe.
44. The lighting fixture of claim 43, wherein: the cavity of the
tube further contains at least one of air, gas, or vacuum; and the
air, gas, or vacuum separating the tube from the frame, the at
least one LED light source, the control circuitry, and the coolant
pipe forms a thermal barrier that reduces transfer of the heat
generated by the at least one LED light source during operation of
the lighting fixture to the agricultural environment.
45. The lighting fixture of claim 42, wherein: the frame thermally
expands due to the heat generated by the at least one LED light
source during operation of the lighting fixture such that a first
length of the frame changes relative to a second length of the
tube; and the first and second end caps deform in response to the
relative change in the first and second lengths so as to remain
coupled to the frame and the tube.
46. The lighting fixture of claim 40, wherein: the cross-sectional
shape of the tube is a circle; and when the lighting fixture is
deployed in the agricultural environment and coupled to a support
structure, the lighting fixture is at least one of rotatably
adjustable or translationally adjustable with respect to the
support structure such that the radiation emitted by the at least
one LED light source is redirected onto different portions of the
agricultural environment when the lighting fixture is moved with
respect to the support structure.
47. A fluid-cooled LED-based lighting fixture, comprising: a frame
having a coolant channel; at least one LED light source, coupled to
the frame, to emit radiation; control circuitry, coupled to the
frame and electrically coupled to the at least one LED light
source, to receive an electrical power input and to control the at
least one LED light source, the electrical power input being
greater than or equal to about 175 W; and a coolant pipe, at least
partially disposed in and thermally coupled to the coolant channel
of the frame, to carry a fluid coolant that extracts heat generated
by the at least one LED light source during operation of the
lighting fixture, wherein the frame, the at least one LED light
source, the control circuitry, and at least a portion of the
coolant pipe are dimensioned to fit within a tube having an
exterior diameter of about 2 inches and an exterior length of about
96 inches.
48. The lighting fixture of claim 47, further comprising: the tube
defining a cavity to contain the frame, the at least one LED light
source, the control circuitry, and at least a portion of the
coolant pipe.
49. The lighting fixture of claim 48, wherein: the tube has a first
open end and a second open end; and the lighting fixture further
comprises: a first end cap disposed at the first open end of the
tube and coupled to the frame, the first end cap having a first
fluidic feedthrough through which the coolant pipe passes through;
and a second end cap disposed at the second open end of the tube
and coupled to the frame, the second end cap having a second
fluidic feedthrough through which the coolant pipe passes through,
the first and second end caps enclosing the cavity of the tube.
50. The lighting fixture of claim 49, wherein the frame is coupled
to the first and second end caps such that the tube does not
physically contact the frame, the at least one LED light source,
the control circuitry, and the coolant pipe.
51. The lighting fixture of claim 50, wherein: the cavity of the
tube further contains at least one of air, gas, or vacuum; and the
air, gas, or vacuum separating the tube from the frame, the at
least one LED light source, the control circuitry, and the coolant
pipe forms a thermal barrier that reduces transfer of the heat
generated by the at least one LED light source during operation of
the lighting fixture to the agricultural environment.
52. The lighting fixture of claim 49, wherein: the frame thermally
expands due to the heat generated by the at least one LED light
source during operation of the lighting fixture such that a first
length of the frame changes relative to a second length of the
tube; and the first and second end caps deform in response to the
relative change in the first and second lengths so as to remain
coupled to the frame and the tube.
53. The lighting fixture of claim 48, wherein: the cross-sectional
shape of the tube is a circle; and when the lighting fixture is
deployed in the agricultural environment and coupled to a support
structure, the lighting fixture is at least one of rotatably
adjustable or translationally adjustable with respect to the
support structure such that the radiation emitted by the at least
one LED light source is redirected onto different portions of the
agricultural environment when the lighting fixture is moved with
respect to the support structure.
54. A fluid-cooled LED-based lighting fixture for an agricultural
environment, comprising: a frame having a coolant channel; at least
one white LED light source, coupled to the frame, to emit
photosynthetically active radiation (PAR) at a first intensity;
control circuitry, coupled to the frame and electrically coupled to
the at least one white LED light source, to receive an electrical
power input and to control the at least one white LED light source,
the electrical power input being greater than or equal to about 175
W, the control circuitry including a dimmer to controllably reduce
the first intensity of the PAR to a second intensity less than the
first intensity; a tube defining a cavity with a first open end and
a second open end, the cavity containing the frame, the at least
one white LED light source, and the control circuitry, the tube
further containing one of air, gas, or vacuum physically separating
the tube from the frame, the at least one white LED light source,
and the control circuitry to form a thermal barrier that reduces
transfer of heat generated by the at least one white LED light
source during operation of the lighting fixture to the agricultural
environment, the tube being transparent to the radiation, the tube
having an exterior diameter of about 2 inches and an exterior
length of about 96 inches; a first end cap disposed at the first
open end of the tube and coupled to the frame; a second end cap
disposed at the second open end of the tube and coupled to the
frame, the first and second end caps enclosing the cavity of the
tube; and a coolant pipe, at least partially disposed in and
thermally coupled to the coolant channel of the frame, to carry a
fluid coolant that extracts heat generated by the at least one
white LED light source during operation of the lighting fixture,
the coolant pipe passing through a first fluidic feedthrough in the
first end cap and a second fluidic feedthrough in the second end
cap.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION(S)
[0001] The present application is a bypass continuation of
international application No. PCT/US2020/064837, filed on Dec. 14,
2020, entitled "FLUID-COOLED LED-BASED LIGHTING FIXTURE IN CLOSE
PROXIMITY GROW SYSTEMS FOR CONTROLLED ENVIRONMENT HORTICULTURE,"
which claims priority to U.S. provisional application No.
62/947,538, filed on Dec. 12, 2019, entitled "FLUID-COOLED
LED-BASED LIGHTING METHODS AND APPARATUS IN CLOSE PROXIMITY GROW
SYSTEMS FOR CONTROLLED ENVIRONMENT HORTICULTURE," each of which is
incorporated herein by reference in its entirety.
BACKGROUND
[0002] Controlled Environment Horticulture (CEH) (also referred to
as Controlled Environment Agriculture or CEA) is the process of
growing plants in a controlled environment where various
environmental parameters are monitored and adjusted to improve the
quality and yield of the plants. Compared to conventional
approaches for plant cultivation, CEH may provide the year-round
cultivation of plants, a grow environment that is insensitive to
variable weather conditions and has fewer pests, healthier plants
that are less prone to disease, and less consumption of resources
on a per plant basis. A CEH system (also referred to herein as a
"controlled agricultural environment") is typically enclosed, at
least in part, by a building structure such as a greenhouse, a grow
room, or a covered portion of a field in order to provide some
degree of control over environmental conditions. A CEH system often
includes one or more artificial lighting systems to supplement
and/or replace natural sunlight, which may be obstructed by the
building structure or insufficient during certain periods of the
year (e.g., winter months). Various types of artificial lighting
systems may be used including, but not limited to, a high intensity
discharge lamp, a light emitting diode (LED), and a fluorescent
lamp.
SUMMARY
[0003] The Inventors have recognized and appreciated CEH systems
have the potential to provide greater control over environmental
conditions to improve the overall quality and yield of plants and
enable deployment in locations that are traditionally not suitable
for agriculture, i.e., non-arable land (e.g., a city, a desert, an
arctic landscape, land with no source of fresh water). However, the
Inventors also recognize previous CEH systems often lack the
flexibility to adaptively tailor environmental conditions for
plants progressing through different stages of growth (e.g., the
vegetative stage, the flowering stage) and/or different plant
species.
[0004] For example, artificial lighting systems in CEH systems
generate an appreciable amount of heat, especially when higher
light levels are desired (e.g., to illuminate plants at the
flowering stage). In some conventional CEH systems, the heat
generated by the artificial lighting systems is dissipated directly
into the agricultural environment. To prevent an undesirable
increase in the environment temperature, conventional CEH systems
often include one or more air conditioners within the agricultural
environment to regulate the environment temperature, resulting in
greater energy consumption.
[0005] In some instances, the CEH system may be a close proximity
grow system where the distance separating the artificial lighting
systems from the plants ranges between 6 inches and 72 inches. The
close proximity between the artificial lighting systems and the
plants may reduce the effectiveness of the air conditioner(s) in
regulating the temperature within the immediate vicinity of the
plants. This, in turn, may necessitate the artificial lighting
systems operate at lower light levels than desired to ensure the
lighting systems do not overheat and/or the plants are not exposed
to excessive temperatures. One example of a close proximity grow
system is a vertical grow rack system where the plants are grown on
multiple, vertically-stacked shelves to provide a higher density
grow area with a smaller footprint.
[0006] Additionally, conventional CEH systems are generally fixed
installations where the artificial lighting systems are deployed at
a predetermined location and/or orientation that can only be
changed with substantial modification and/or reassembly of the CEH
system. As a result, each lighting fixture typically emits
radiation that only illuminates one side or one portion of the
plants and cannot be readily adjusted to illuminate a different
side or a different portion of the plants. Returning again to the
example of a vertical grow rack system, the lighting fixture(s) in
a conventional vertical grow rack system are typically affixed to a
rack, thus constraining the lateral spacing and orientation of the
lighting fixture(s) and, thus, the illumination profile of the
radiation (e.g., spatial and angular distribution of radiation)
incident on the plants. For some plants, it may be desirable to
illuminate different sides of the plants to simulate illumination
by the sun during a typical day cycle. However, this may only be
accomplished by the addition of more lighting fixtures given the
fixed installation of the artificial lighting systems or by
disassembling and reassembling the lighting system to change the
locations of the lighting fixtures.
[0007] In view of the foregoing limitations of conventional CEH
systems and lighting fixtures, the present disclosure is thus
directed to various implementations of a compact LED-based lighting
fixture for CEH systems with an integrated fluid cooling system
that enables higher light levels while reducing the amount of heat
dissipated to the environment.
[0008] The lighting fixture may generally include a frame to
mechanically support one or more LED modules. Each LED module may
include one or more LED light sources that emit radiation with
different spectral content (e.g., photosynthetically active
radiation or PAR, infrared radiation, ultraviolet radiation) to
illuminate one or more plants. The frame may also support control
circuitry (also referred to as the "circuitry board" or the
"processor") to electrically power and control the LED module(s).
The control circuitry may provide several functions to the
operation of the lighting fixture including, but not limited to,
receiving alternate current (AC) power, supplying direct current
(DC) power to the LED module(s), adjusting an operating parameter
of the LED module(s) (e.g., the total intensity, the spectral
intensity at a particular wavelength or wavelength band, turning
the LED module(s) on or off, adjusting the rate of change with
which the total intensity or spectral intensity is changed), and
transmitting sensory data acquired by sensors and/or cameras (also
referred to herein as "imaging systems") integrated within the
lighting fixture and/or electrically connected to the lighting
fixture (e.g., the lighting fixture temperature, the operating
status or operating conditions of the lighting fixture). In this
manner, the lighting fixture may provide lighting, power
electronics, and data communication integrated into a single
device. In some implementations, the control circuitry may also
provide a dimmer to adjust the radiation output of the LED
module(s). For example, the dimmer may reduce the intensity of
radiation down to 1% of the nominal intensity when the dimmer is
not activated.
[0009] The lighting fixture may further include one or more coolant
pipes coupled to the frame to carry a flow of fluid coolant to
extract the heat generated by the LED module(s). In some
implementations, the coolant pipe(s) may be press-fit or crush-fit
into respective coolant channel(s) formed along a portion of the
frame to increase thermal contact. The coolant pipe(s) may be
formed from various materials, such as a copper due, in part, to
its antimicrobial and antifouling properties. The coolant pipes may
be further plated with nickel.
[0010] In some implementations, the frame may be shaped and/or
dimensioned such that the coolant channel(s) and, hence, the
coolant pipe(s) are disposed between the LED module(s) and the
control circuitry. In this manner, the fluid coolant may extract
the heat generated by the LED module(s) while reducing or, in some
instances, preventing the control circuitry from being heated by
the LED module(s). Said in another way, the frame may be structured
to provide a thermal break or barrier between the LED module(s) and
the control circuitry such that the heat generated by the LED
module(s) is primarily transferred to the fluid coolant.
[0011] In some implementations, the frame may be an assembly of
multiple components supporting the LED module(s) and the control
circuitry. For example, the frame may include a first frame
component to support the LED module(s) and a second frame component
to support the control circuitry. The first frame component may
include the coolant channel(s) formed therein and may be formed
from a thermally conductive material, such as aluminum, to conduct
the heat generated by the LED module(s) to the coolant pipe(s). The
second frame component may be formed from an electrically
insulating material, such as plastic, to electrically isolate the
control circuitry from the other components of the lighting
fixture. In some implementations, the first frame component may
span a length of the lighting fixture while the second frame
component may only span a portion of the length of the lighting
fixture.
[0012] The first frame component may also have at least two sides
that each have mounting channels formed therein to support the LED
module(s) and the second frame component. In particular, one or
more LED modules may be slidably positioned along one of the
mounting channels of the first frame component and secured to the
first frame component using various coupling mechanisms including,
but not limited to, a zip tie and a fastener. Similarly, the second
frame component supporting the control circuitry may also be
slidably positioned along a mounting of the first frame component
and coupled to the first frame component using, for example, a zip
tie and/or a fastener.
[0013] In some implementations, the LED modules may be disposed on
different sides of the frame to provide bi-directional,
tri-directional, quad-directional, and/or omni-directional lighting
from the lighting fixture. In other words, the LED modules may be
positioned and/or oriented to emit radiation in different
directions having an angular distribution up to 4.pi. steradians.
This may be accomplished, in part, by the frame having multiple
sides to support the multiple LED modules. It should be appreciated
the frame may still support one or more coolant channels for
coolant pipes arranged to extract the heat generated from each LED
module. Furthermore, it should also be appreciated the frame may
have a structure that forms a thermal break or barrier to reduce
or, in some instances, prevent heating of the control circuitry by
the LED modules.
[0014] Additionally, the lighting fixture may further include an
enclosure, such as a tube, that surrounds and encapsulates the
frame, the LED module(s), the control circuitry, and at least a
portion of the coolant pipe. For example, the lighting fixture may
include a tube that spans the length of the lighting fixture and
defines a cavity to contain the frame, the LED module(s), the
control circuitry, and at least a portion of the coolant pipe. The
tube may thus be transparent to the radiation emitted by the LED
module(s). The tube may further include a first open end and a
second open end, which may each be covered by end caps, thus
sealing the cavity of the tube. The cooling pipe may be routed
through respective fluidic feedthroughs of each end cap and the
electrical cable(s) providing electrical power and/or data
communication may be routed through an electrical feedthrough on
one or both of the end caps.
[0015] In some implementations, the tube and the end caps may
sufficiently seal the cavity to reduce or, in some instances,
prevent the infiltration of dust, dirt, and/or water. For example,
the end caps may form a water-resistant seal with the tube to
protect the various components disposed within the cavity of the
tube. In some implementations, the water-resistant seal may also
enable the lighting fixture to be submerged in a liquid (e.g.,
water) to illuminate the plants (e.g., algae, seaweed).
Additionally, the tube and the end caps may provide a smooth
exterior surface that may be more easily cleaned compared to
conventional lighting fixtures, which often include corrugated
exterior surfaces for convective air cooling (e.g., heat fins) or
for manufacturability (e.g., recesses to reduce the weight of the
lighting fixture).
[0016] In some implementations, the tube may be shaped and/or
dimensioned to reduce or, in some instances, eliminate physical
contact with the frame, the LED module(s), the control circuitry,
and the portion of the coolant pipe disposed within the cavity of
the tube. The tube may further contain air, gas (e.g., an inert gas
such as argon or nitrogen), or vacuum separating the tube from the
various components disposed therein to provide a thermally
insulating barrier that reduces or, in some instances, prevents the
heat generated by the LED module(s) from being dissipated directly
into the surrounding environment.
[0017] The tube and the end caps may also enable the lighting
fixture to be translationally and/or rotationally adjustable, thus
enabling the user to change the illumination profile of the
lighting fixture after installation. For example, the lighting
fixture may be coupled to a support structure in the environment
(e.g., a rack structure) by a clamping mechanism (e.g., a swivel
joint clamp) that enables rotation of the lighting fixture about a
longitudinal axis of the tube while mechanically constraining the
other translational and rotational degrees of freedom. In another
example, the lighting fixture may be coupled to the support
structure by a commodity clamp that provides sufficient clearance
for the tube to be slidably adjustable along the longitudinal axis
of the tube. This may enable adjustments to the lateral spacing
between neighboring lighting fixtures in the CEH system,
particularly if the lighting fixtures are electrically and
fluidically coupled to one another via compliant cabling and/or
hoses. In yet another example, the lighting fixture may be coupled
to a motorized, electronically controllable clamping mechanism that
provides translational and/or rotational adjustment of the lighting
fixture. Thus, a single lighting fixture may be adjusted to
provide, for example, simulated sunlight.
[0018] The tube may be formed from various materials including, but
not limited to, glass (e.g., quartz), polycarbonate, acrylic, and
polymethylmethacrylate (PMMA). The tube may generally provide a
transmittance greater than or equal to about 80% and, more
preferably, greater than or equal to 90% across various wavelength
regimes including, but not limited to, ultraviolet, visible,
near-infrared, mid-infrared, and long-infrared wavelength ranges.
Depending on the materials used to form the tube 1300, various
methods of manufacture may be utilized including, but not limited
to, extrusion, injection molding, blow molding, and manual molding.
For instances where the tube 1300 is assembled from multiple parts,
various coupling mechanisms may be used for assembly including, but
not limited to, snap fits, screw fasteners, bolt fasteners,
adhesives, brazing, and welding.
[0019] In some implementations, each end cap may be a two-part
assembly that includes an end cap support that couples to the frame
and an end cap cover that covers an open end of the tube and the
end cap support. The end cap support and the end cap cover may
together form a clamp that couples the tube to the end cap. In some
implementations, a clamp may couple the end cap cover to the
tube.
[0020] In some implementations, the frame of the lighting fixture
may thermally expand during operation due to the heat generated by
the LED module(s). To accommodate a change in length of the frame,
the end cap cover may be formed from a compliant material that
deforms in shape as the frame thermally expands (or contracts). The
compliance of the end cap cover may further ensure the end cap
remains coupled to the tube so that the cavity remains
substantially sealed or sealed. In some implementations, the end
cap support may be formed from a rigid plastic or polymer
including, but not limited to, polycarbonate and glass-filled
polycarbonate. In some implementations, the end cap cover may be
formed from a compliant plastic or polymer including, but not
limited to, urethane, rubber, and silicone.
[0021] The integrated fluid cooling system in the lighting fixture
may enable a power density, defined as the ratio of the electrical
power input to the exterior length or volume of the lighting
fixture and/or the volume of the grow space, appreciably higher
than conventional lighting fixtures. For example, the lighting
fixture may nominally have a width (e.g., the exterior width of the
frame or the tube) of about 2 inches and a length (e.g., the
exterior length of the fame or the tube) of ranging between about
48 and about 96 inches. Generally, the length of the lighting
fixture may correspond to standard rack lengths in a vertical grow
rack system. The lighting fixture may further receive AC power that
may scale with the length of the lighting fixture.
[0022] For example, the lighting fixture may receive an AC power
greater than or equal to about 175 W for a length of about 96
inches, resulting in a power density per unit length of the
lighting fixture greater than or equal to about 1.8 W per inch. If
the lighting fixture further has a width of about 2 inches, the
power density per unit volume of the lighting fixture may be
greater than or equal to about 0.6 W per cubic inches. In another
example, the power density per unit volume of the grow space may be
greater than about 5 W per cubic feet corresponding to an AC power
of about 175 W and a cubic grow space volume with 3.27 feet (i.e.,
1 m) long sides. These dimensions may enable the lighting fixture
to be installed in close proximity grow systems, such as a vertical
grow rack system. The combination of the electrical power input and
the cooling provided by the coolant pipes may enable the lighting
fixture to provide higher light levels to illuminate plants across
later growth stages.
[0023] The lighting fixture may generally receive electrical power
and data communication via one or more electrical cables. In some
implementations, the electrical cable(s) may be routed through an
electrical feedthrough in the end caps. In some implementations,
the lighting fixture may include one or more power and/or
communication ports. The power and/or communication ports may be
various types of ports including, but not limited to, a Universal
Serial Bus (USB) port, a Power over Ethernet (PoE) port, a RS-485
port, a power line carrier (PLC) port, and a wireless communication
device (e.g., WiFi). The electrical power may be AC power supplied
at a voltage ranging between 208 V to 277 V and a current ranging
between 15 A and 30 A.
[0024] In some implementations, the lighting fixture may include a
port that provides both electrical power and data communication.
For example, the lighting fixture may include a PLC port to connect
to a PLC cable with a single conductor (e.g., a single wire) that
carries both power and data signals. The control circuitry may
include electronics to extract the data signals from the power. In
this manner, a single electrical cable may be connected to the
lighting fixture, thus simplifying installation.
[0025] Additionally, the electrical cable (also referred to herein
as the "electrical cable assembly") that is coupled to the lighting
fixture may include one or more drop tee connectors to provide
multiple branches to provide electrical power and/or data
communication to other lighting fixtures. In other words, the
electrical cable assembly may supply power and data communication
to an array of lighting fixtures, further simplifying installation.
In some implementations, the electrical cable assembly may be a
modular configuration where multiple drop tee connectors and cables
may be coupled together based on the number of lighting fixtures
being connected together.
[0026] Various sensors may be integrated into the lighting fixture
and/or communicatively coupled to the lighting fixture including,
but not limited to, a light temperature sensor to monitor the
temperature of the LED module(s), a cold-side fluid coolant
temperature sensor to measure the temperature of the fluid coolant
entering the coolant pipe of the lighting fixture, a hot-side fluid
coolant temperature sensor to measure the temperature of the fluid
coolant exiting the coolant pipe of the lighting fixture, an
ambient air temperature sensor, a relative humidity sensor, a
carbon dioxide sensor, an air speed sensor, and a camera.
[0027] In one exemplary implementation, a fluid-cooled LED-based
lighting fixture for an agricultural environment includes a frame
having a coolant channel, at least one LED light source coupled to
the frame to emit radiation, control circuitry coupled to the frame
and electrically coupled to the at least one LED light source to
receive AC power and to control the at least one LED light source,
a tube defining a cavity with a first open end and a second open
end where the cavity contains the frame, the at least one LED light
source, and the control circuitry and the tube is transparent to
the radiation, a first end cap disposed at the first open end of
the tube and coupled to the frame, a second end cap disposed at the
second open end of the tube and coupled to the frame where the
first and second end caps enclosing the cavity of the tube, and a
coolant pipe at least partially disposed in and thermally coupled
to the coolant channel of the frame to carry a fluid coolant that
extracts heat generated by the at least one LED light source during
operation of the lighting fixture where the coolant pipe passes
through a first fluidic feedthrough in the first end cap and a
second fluidic feedthrough in the second end cap.
[0028] In another exemplary implementation, a fluid-cooled
LED-based lighting fixture includes a frame with a first frame
component having a first side and a second side opposite the first
side where the second side has a coolant channel formed therein and
a second frame component coupled to the second side of the first
frame component. The lighting fixture further includes at least one
LED light source coupled to the first frame component to emit
radiation, control circuitry coupled to the second frame component
and electrically coupled to the at least one LED light source to
receive AC power and to control the at least one LED light source,
and a coolant pipe at least partially disposed in and thermally
coupled to the coolant channel of the first frame component to
carry a fluid coolant that extracts heat generated by the at least
one LED light source. The first frame component thermally conducts
the heat generated by the at least one LED light source to the
coolant pipe and the second frame component electrically isolates
the control circuitry from the first frame component.
[0029] In another exemplary implementation, a fluid-cooled
LED-based lighting fixture includes a frame having a coolant
channel, at least one LED light source coupled to the frame to emit
radiation, control circuitry coupled to the frame and electrically
coupled to the at least one LED light source to receive an
electrical power input and to control the at least one LED light
source where the electrical power input being greater than or equal
to about 175 W, and a coolant pipe at least partially disposed in
and thermally coupled to the coolant channel of the frame to carry
a fluid coolant that extracts heat generated by the at least one
LED light source during operation of the lighting fixture. The
frame, the at least one LED light source, the control circuitry,
and at least a portion of the coolant pipe are dimensioned to fit
within a tube having an exterior diameter of about 2 inches and an
exterior length of about 96 inches.
[0030] In another exemplary implementation, a fluid-cooled
LED-based lighting fixture for an agricultural environment includes
a frame having a coolant channel, at least one white LED light
source coupled to the frame to emit photosynthetically active
radiation (PAR) at a first intensity, control circuitry coupled to
the frame and electrically coupled to the at least one white LED
light source to receive an electrical power input and to control
the at least one white LED light source where the electrical power
input is greater than or equal to about 175 W and the control
circuitry includes a dimmer to controllably reduce the first
intensity of the PAR to a second intensity less than the first
intensity, a tube defining a cavity with a first open end and a
second open end where the cavity contains the frame, the at least
one white LED light source, and the control circuitry and further
contains one of air, gas, or vacuum physically separating the tube
from the frame, the at least one white LED light source, and the
control circuitry to form a thermal barrier that reduces transfer
of heat generated by the at least one white LED light source during
operation of the lighting fixture to the agricultural environment,
a first end cap disposed at the first open end of the tube and
coupled to the frame, a second end cap disposed at the second open
end of the tube and coupled to the frame, the first and second end
caps enclosing the cavity of the tube, and a coolant pipe at least
partially disposed in and thermally coupled to the coolant channel
of the frame to carry a fluid coolant that extracts heat generated
by the at least one white LED light source during operation of the
lighting fixture, the coolant pipe passing through a first fluidic
feedthrough in the first end cap and a second fluidic feedthrough
in the second end cap. The tube is also transparent to the
radiation and the tube has an exterior diameter of about 2 inches
and an exterior length of about 96 inches.
[0031] It should be appreciated that all combinations of the
foregoing concepts and additional concepts discussed in greater
detail below (provided such concepts are not mutually inconsistent)
are contemplated as being part of the inventive subject matter
disclosed herein. In particular, all combinations of claimed
subject matter appearing at the end of this disclosure are
contemplated as being part of the inventive subject matter
disclosed herein. It should also be appreciated that terminology
explicitly employed herein that also may appear in any disclosure
incorporated by reference should be accorded a meaning most
consistent with the particular concepts disclosed herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The skilled artisan will understand that the drawings
primarily are for illustrative purposes and are not intended to
limit the scope of the inventive subject matter described herein.
The drawings are not necessarily to scale; in some instances,
various aspects of the inventive subject matter disclosed herein
may be shown exaggerated or enlarged in the drawings to facilitate
an understanding of different features. In the drawings, like
reference characters generally refer to like features (e.g.,
functionally similar and/or structurally similar elements).
[0033] FIG. 1A shows a conventional controlled agricultural
environment where one or more HPS lamps are used.
[0034] FIG. 1B shows a conventional controlled agricultural
environment where one or more conventional LED-based lighting
fixtures are used.
[0035] FIG. 1C shows an exemplary controlled agricultural
environment where one or more fluid-cooled LED-based lighting
fixtures are retrofit into a pre-existing environment, according to
some implementations of the disclosure.
[0036] FIG. 1D shows an exemplary controlled agricultural
environment where one or more fluid-cooled LED-based lighting
fixtures are coupled to a hydronics system, according to some
implementations of the disclosure.
[0037] FIG. 2A shows a bottom perspective view of an exemplary
fluid-cooled LED-based lighting fixture having a tube
enclosure.
[0038] FIG. 2B-1 shows a front view of a first portion of the
lighting fixture of FIG. 2A.
[0039] FIG. 2B-2 shows a front view of a second portion of the
lighting fixture of FIG. 2B-1.
[0040] FIG. 2C-1 shows a bottom view of the first portion of the
lighting fixture of FIG. 2B-1.
[0041] FIG. 2C-2 shows a bottom view of the second portion of the
lighting fixture of FIG. 2B-2.
[0042] FIG. 2D shows a right-side view of the lighting fixture of
FIG. 2A.
[0043] FIG. 2E shows an exploded bottom perspective view of the
lighting fixture of FIG. 2A.
[0044] FIG. 2F shows an exploded top perspective view of the
lighting fixture of FIG. 2A.
[0045] FIG. 2G shows another exploded bottom perspective view of
the lighting fixture of FIG. 2A.
[0046] FIG. 2H shows another exploded top perspective view of the
lighting fixture of FIG. 2A.
[0047] FIG. 2I shows a cross-sectional view of the lighting fixture
of FIG. 2A corresponding to the plane A-A of FIG. 2B-2.
[0048] FIG. 3 shows a top perspective view of a frame and a tube in
the lighting fixture of FIG. 2A.
[0049] FIG. 4A shows a top perspective view of an end cap in the
lighting fixture of FIG. 2A.
[0050] FIG. 4B shows a left-side view of the end cap of FIG. 4A
with a commodity clamp.
[0051] FIG. 4C shows a side view of the end cap coupled to the
frame and the tube in the lighting fixture of FIG. 2A at a first
temperature.
[0052] FIG. 4D shows a side view of the end cap coupled to the
frame and the tube in the lighting fixture of FIG. 4C at a second
temperature greater than the first temperature where the frame
undergoes thermal expansion.
[0053] FIG. 5A shows a top perspective view of an end cap support
in the end cap of FIG. 4A.
[0054] FIG. 5B shows a left-side view of the end cap support of
FIG. 5A.
[0055] FIG. 5C shows a top view of the end cap support of FIG.
5A.
[0056] FIG. 5D shows a front view of the end cap support of FIG.
5A.
[0057] FIG. 6A shows a top perspective view of an end cap cover in
the end cap of FIG. 4A.
[0058] FIG. 6B shows a bottom perspective view of the end cap cover
of FIG. 6A.
[0059] FIG. 6C shows a right-side view of the end cap cover of FIG.
6A.
[0060] FIG. 6D shows a top view of the end cap cover of FIG.
6A.
[0061] FIG. 6E shows a front view of the end cap cover of FIG.
6A.
[0062] FIG. 7A shows a bottom perspective view of an exemplary LED
module having four rows of LED light sources.
[0063] FIG. 7B shows a bottom view of the LED module of FIG.
7A.
[0064] FIG. 7C shows a top view of the LED module of FIG. 7A.
[0065] FIG. 7D shows a rear view of the LED module of FIG. 7A.
[0066] FIG. 7E shows a right-side view of the LED module of FIG.
7A.
[0067] FIG. 8A shows a bottom perspective view of an exemplary LED
module having two rows of LED light sources.
[0068] FIG. 8B shows a bottom view of the LED module of FIG.
8A.
[0069] FIG. 8C shows a top view of the LED module of FIG. 8A.
[0070] FIG. 8D shows a rear view of the LED module of FIG. 8A.
[0071] FIG. 8E shows a right-side view of the LED module of FIG.
8A.
[0072] FIG. 9A shows a top perspective view of control circuitry in
the lighting fixture of FIG. 2A.
[0073] FIG. 9B shows a top view of the control circuitry of FIG.
9A.
[0074] FIG. 9C shows a bottom view of the control circuitry of FIG.
9A.
[0075] FIG. 9D shows a front view of the control circuitry of FIG.
9A.
[0076] FIG. 9E shows a right-side view of the control circuitry of
FIG. 9A.
[0077] FIG. 10A shows an exemplary mounting clamp to couple the
lighting fixture of FIG. 2A to a rack.
[0078] FIG. 10B shows another exemplary mounting clamp.
[0079] FIG. 10C shows an exemplary zip tie to couple the lighting
fixture of FIG. 2A to a rack.
[0080] FIG. 11A shows a block diagram of the control circuitry of
FIG. 9A.
[0081] FIG. 11B-1 shows a first portion of a circuit diagram
corresponding to the control circuitry of FIG. 9A.
[0082] FIG. 11B-2 shows a second portion of a circuit diagram
corresponding to the control circuitry of FIG. 9A.
[0083] FIG. 11B-3 shows a third portion of a circuit diagram
corresponding to the control circuitry of FIG. 9A.
[0084] FIG. 11B-4 shows a fourth portion of a circuit diagram
corresponding to the control circuitry of FIG. 9A.
[0085] FIG. 12A shows a circuit diagram of various electrical
components in the control circuitry of FIG. 9A, according to some
implementations of the disclosure.
[0086] FIG. 12B shows a circuit diagram of the bias and control
power supply in the control circuitry of FIG. 12A.
[0087] FIG. 12C shows a circuit diagram of an optional DC-DC
converter.
[0088] FIG. 12D shows a circuit diagram of the AC line sensor in
the control circuitry of FIG. 12A.
[0089] FIG. 12E shows a circuit diagram of the digital signal
processor (DSP) in the control circuitry of FIG. 12A.
[0090] FIG. 12F shows a circuit diagram of the temperature sensor
circuitry in the control circuitry of FIG. 12A.
[0091] FIG. 12G shows a circuit diagram of the boost circuit in the
control circuitry of FIG. 12A.
[0092] FIG. 12H shows a circuit diagram of another boost circuit in
the control circuitry FIG. 12A.
[0093] FIG. 12I shows a circuit diagram of an electrical power
coupler and a PLC module in the control circuitry of FIG. 12A.
[0094] FIG. 13A-1 shows a top view of a first portion of another
exemplary lighting fixture with a tube enclosure.
[0095] FIG. 13A-2 shows a top view of a second portion of the
lighting fixture of FIG. 13A.
[0096] FIG. 13B shows a bottom perspective view of a LED module
mounted to a frame disposed within a tube in the lighting fixture
of FIGS. 13A-1 and 13A-2.
[0097] FIG. 13C shows a top perspective view of a second end cap
mounted to a tube and a pipe in the lighting fixture of FIGS. 13A-1
and 13A-2.
[0098] FIG. 13D shows a top perspective view of the lighting
fixture of FIG. 13C with a cable and a feedthrough connector
removed.
[0099] FIG. 13E shows a right-side view of a frame and the LED
module in the lighting fixture of FIGS. 13A-1 and 13A-2.
[0100] FIG. 14 shows a cross-sectional view of another exemplary
lighting fixture providing bi-directional lighting
(interlighting).
[0101] FIG. 15A shows a right-side view of an exemplary lighting
fixture with a RS-485 port.
[0102] FIG. 15B shows a right-side view of an exemplary lighting
fixture with a Universal Serial Bus (USB) port.
[0103] FIG. 15C shows a right-side view of an exemplary lighting
fixture with a Power over Ethernet (PoE) port.
[0104] FIG. 16A shows a perspective view of another exemplary
electrical cable assembly with flag connectors.
[0105] FIG. 16B shows a side view of the electrical cable assembly
of FIG. 16A.
[0106] FIG. 16C shows a magnified view of the electrical cable
assembly of FIG. 16A fed through an end cap in the lighting fixture
of FIG. 2A.
DETAILED DESCRIPTION
[0107] Following below are more detailed descriptions of various
concepts related to, and implementations of, a fluid-cooled
LED-based lighting fixture for a close proximity grow system. It
should be appreciated that various concepts introduced above and
discussed in greater detail below may be implemented in numerous
ways. Examples of specific implementations and applications are
provided primarily for illustrative purposes so as to enable those
skilled in the art to practice the implementations and alternatives
apparent to those skilled in the art.
[0108] The figures and example implementations described below are
not meant to limit the scope of the present implementations to a
single embodiment. Other implementations are possible by way of
interchange of some or all of the described or illustrated
elements. Moreover, where certain elements of the disclosed example
implementations may be partially or fully implemented using known
components, in some instances only those portions of such known
components that are necessary for an understanding of the present
implementations are described, and detailed descriptions of other
portions of such known components are omitted so as not to obscure
the present implementations.
[0109] In the discussion below, various examples of inventive
lighting fixtures are provided, wherein a given example or set of
examples showcases one or more particular features of a frame, a
LED module, control circuitry, a tube, and an end cap. It should be
appreciated that one or more features discussed in connection with
a given example of components of a lighting fixture may be employed
in other examples of lighting fixtures according to the present
disclosure, such that the various features disclosed herein may be
readily combined in a given system according to the present
disclosure (provided that respective features are not mutually
inconsistent).
[0110] Certain dimensions and features of the lighting fixture are
described herein using the terms "approximately," "about,"
"substantially," and/or "similar." As used herein, the terms
"approximately," "about," "substantially," and/or "similar"
indicates that each of the described dimensions or features is not
a strict boundary or parameter and does not exclude functionally
similar variations therefrom. Unless context or the description
indicates otherwise, the use of the terms "approximately," "about,"
"substantially," and/or "similar" in connection with a numerical
parameter indicates that the numerical parameter includes
variations that, using mathematical and industrial principles
accepted in the art (e.g., rounding, measurement or other
systematic errors, manufacturing tolerances, etc.), would not vary
the least significant digit.
A Fluid-Cooled LED-Based Lighting Fixture
[0111] Controlled Environment Horticulture (CEH) (also referred to
as controlled environment agriculture or CEA) is the process of
growing plants in a controlled environment where various
environmental parameters, such as lighting, temperature, humidity,
nutrient levels, soil moisture, and carbon dioxide (CO.sub.2)
concentrations are monitored and adjusted to improve the quality
and yield of the plants. Compared to conventional approaches of
plant cultivation, CEH may enable year-round production of plants,
insensitivity to variable weather conditions, reduce pests and
diseases, and reduce the amount of resources consumed on a per
plant basis. Additionally, the general concepts of CEH may be
applied to various types of growing systems including, but not
limited to soil-based systems and hydroponics systems.
[0112] A controlled agricultural environment is typically enclosed,
at least in part, by a building structure such as a greenhouse, a
grow room, or a covered portion of a field in order to provide some
degree of control over environmental conditions. One or more
artificial lighting systems are often used in such controlled
agricultural environments to supplement and/or replace natural
sunlight that may be obstructed by the building structure or
insufficient during certain periods of the year (e.g., winter
months). The use of an artificial lighting system may also provide
yet another measure of control where the intensity and spectral
characteristics of the lighting system may be tailored to improve
the photosynthetic rates of plants. Various types of artificial
lighting systems may be used including, but not limited to, a high
intensity discharge lamp, a light emitting diode (LED), and a
fluorescent lamp.
[0113] Artificial lighting systems, however, generate heat, which
when dissipated into the environment may contribute appreciably to
the cooling load of the controlled agricultural environment. In
order to accommodate the higher cooling load and thus maintain the
controlled agricultural environment within a desired temperature
envelope, the cooling capacity of a cooling system may need to be
increased resulting in greater energy consumption. For a controlled
agricultural environment on a variable energy budget, greater
energy consumption may lead to higher energy costs. Alternatively,
for a controlled environment on a fixed energy budget, a larger
portion of the energy budget may be consumed by the cooling system,
thus reducing the energy and capacity available to support a larger
growing area.
[0114] To illustrate the impact that excess heat generated by an
artificial lighting system has on energy consumption, FIG. 1A shows
a conventional controlled agricultural environment 20a with one or
more high pressure sodium (HPS) lamps 10, which is a particular
type of high intensity discharge lamp used to irradiate a plurality
of plants 900. The exemplary controlled agricultural environment
20a shown in FIG. 1A further includes a dehumidifier 65 to manage
the relative humidity of the environment and an air conditioner 85,
which may include a fan coil, compressor, and condenser. Energy
consumption by the air conditioner 85 generally depends on (1) the
total cooling load of the environment and (2) the energy efficiency
ratio (EER) of the air conditioner 85. The EER of an air
conditioner is defined as the ratio of the cooling capacity (in
Watts) to the input power (in Watts) at a given operating point.
The EER was calculated with a 35.degree. C. (95.degree. F.) outside
temperature and an inside (return air) temperature of 26.7.degree.
C. (8.degree. F.) and 50% relative humidity. A higher EER indicates
the air conditioner 85 is more efficient.
[0115] As shown in FIG. 1A, the HPS lamps 10 may increase the
cooling load of the environment by (1) dissipating heat
convectively and/or radiatively directly into the environment and
(2) increasing the relative humidity of the environment and thus,
the power input and resultant heat generated by the dehumidifier
65. The cooling load in this exemplary controlled agricultural
environment is about 1315 W. For an EER ranging from 3 to 7, the
input power for the air conditioner thus ranges from 450 to 190 W,
respectively. Based on the input power to the HPS lamps 10 of 1009
W and the dehumidifier 65 of 265 W, the air conditioner 85 thus
consumes about 13% and 26% of the total energy budget,
corresponding to an EER of 7 and 3, respectively. Furthermore, the
heat dissipated by the HPS lamps 10 may give rise to appreciably
large temperature differences in the environment, which, in some
instances, may compromise the temperatures of different growing
areas (e.g., the air conditioner 85 may cause one growing area to
become too cold in order to compensate the heat dissipated in
another growing area).
[0116] The amount of heat generated may vary depending on the type
of lighting system used. However, artificial lighting systems for
controlled agricultural environments may have large power inputs
(e.g., greater than 1000 W) in order to sustain a desired level of
photosynthetically active radiation (PAR) and/or may operate in
confined spaces (e.g., a close proximity grow system). Thus, the
heat generated by various types of lighting systems may still
constitute a large portion of the heat produced within the
environment.
[0117] In another example, FIG. 1B shows a conventional controlled
agricultural environment 20b where one or more conventional
LED-based lighting fixtures 12A and 12B irradiate a plurality of
plants 900. In the controlled agricultural environment 20b, the
LED-based lighting fixtures 12A and 12B dissipates heat primarily
via convection, which may reduce the power input and heat generated
by the dehumidifier 65. In this example, the total cooling load is
about 1210 W. For an EER ratio ranging from 3 to 7, the input power
for the air conditioner 85 ranges from 405 W to 175 W. Compared to
the controlled agricultural environment 20a, the LED-based lighting
fixtures 12A and 12B decreases the total energy budget of the
controlled agricultural environment 20b. However, the proportion of
energy used by the air conditioner 85 remains similar to the first
example at about 13% and 25% for an EER ratio of 7 and 3,
respectively.
[0118] As shown in the two exemplary controlled agricultural
environments 20a and 20b, artificial lighting systems may generate
a substantial amount of heat, which may result in air conditioning
systems consuming a substantial portion of the total energy budget
in a controlled agricultural environment. Furthermore, the heat
generated by the artificial lighting systems is directly dissipated
into the environment in an uncontrolled manner, thus making it more
challenging to regulate the temperature of the environment.
[0119] For these reasons, the lighting fixtures disclosed herein
utilize LED light sources to lower the total energy budget in
combination with an integrated fluid-cooled system to extract a
substantial portion of the heat generated by the LED light sources.
In this manner, the amount of heat transferred to the environment
by the lighting fixture may be substantially reduced or, in some
instances, eliminated, thus decreasing the cooling load. In some
implementations, the lower cooling load may reduce the energy input
for any air conditioning systems in the controlled agricultural
environment. However, it should be appreciated that, in other
implementations, the cooling load may be reduced to such an extent
that the air conditioning systems may be eliminated from the
controlled agricultural environment.
[0120] FIG. 1C shows an exemplary implementation of a controlled
agricultural environment 2000A (also referred to herein as a CEH
system 2000A) with a fluid-cooled LED-based lighting fixture 1000
retrofit into a pre-existing environment that includes a
dehumidifier 65 and an air conditioner 85. While not shown
explicitly in FIG. 1C, the environment may be constituted, at least
in part, by a building structure to house a plurality of plants
900, one or more lighting fixtures 1000, and other equipment. The
lighting fixture 1000 is cooled by a fluid coolant 800 that
circulates through a fluid coolant circuit 570 of a hydronics
system 501. Heat carried by the fluid coolant 800 is removed by a
cooling tower 557 (i.e., the heat rejection device) located outside
of the controlled agricultural environment 2000A. The coolant
circuit 570 may include one or more pumps, regulators and/or valves
555 to control the flow of the fluid coolant 800 in the fluid
coolant circuit 570.
[0121] As shown in FIG. 1C, the pumps, regulators, and/or valves
555 may generate a flow of fluid coolant 800 that enters the
lighting fixture 1000 with a colder temperature Tc and exits the
lighting fixture 1000a with a hotter temperature TH. The rise in
temperature of the fluid coolant 800 is due, in part, to the
convective heating of the fluid 800 as it passes through the
lighting fixture 1000 where the heat is primarily generated by one
or more LED modules in the lighting fixture 1000.
[0122] The fluid coolant 800 may thus capture and transport heat
generated by the lighting fixture 1000, which substantially reduces
the cooling load of the environment and, hence, the power inputs to
the air conditioner 85 and/or the dehumidifier 65. As shown in FIG.
1C, the cooling load for the controlled agricultural environment
2000A is about 635 W, which is approximately 50% of the cooling
load in the controlled agricultural environments 20a and 20b. For
an EER ranging from 3 to 7, the input power for the air conditioner
thus ranges from 210 W to 90 W, respectively. Based on the input
power to the lighting fixture 1000 of 1009 W and the dehumidifier
65 of 160 W, the air conditioner 85 thus consumes about 7% and 15%
of the total energy budget, corresponding to an EER of 7 and 3,
respectively. Additionally, the heat dissipated to the environment
may also be appreciable reduced, thus reducing large temperature
gradients in the environment.
[0123] Although a cooling tower 557 is shown in FIG. 1C to provide
evaporative cooling of the heated fluid coolant 800, it should be
appreciated that other types of heat rejection devices may be used
to remove heat from the fluid coolant 800. Some examples of heat
rejection devices include, but are not limited to, various types of
evaporative coolers, "free" coolers, chillers, dry coolers, air
source coolers, ground source heat exchangers, water source heat
exchangers, or any combinations of the foregoing.
[0124] In another example, FIG. 1D shows an exemplary controlled
agricultural environment 2000B where a lighting fixture 1000 is
coupled to a coolant circuit 570 of a hydronics system 501. The
hydronics system 501 includes multiple fluid circuits 700A and
700B, which regulate and/or maintain the temperature of various
portions of the controlled agricultural environment 2000B and/or
space near the controlled agricultural environment 2000B (e.g., a
hot pool, the growing area) by utilizing the waste heat generated
by the lighting fixture 1000 as a heat source. The coolant circuit
570 may receive heat from the lighting fixture 1000 and other
environment sources (e.g., a dehumidifier 65, the ambient air).
This excess heat generated in the environment may be substantially
removed to further improve the energy savings when operating the
controlled agricultural environment 2000B. In some implementations,
the cooling load may be sufficiently reduced so as to eliminate the
air conditioning systems entirely (i.e., there is no air
conditioner fan coil, compressor or condenser).
[0125] As shown in FIG. 1D the controlled agricultural environment
2000B may include a dehumidifier 65 to regulate the relative
humidity of the environment. The coolant circuit 570 may direct
fluid coolant 800 heated by the lighting fixture 1000 into the
dehumidifier 65 to further remove heat generated by the
dehumidifier 65 in a convective manner similar to the removal of
heat from the lighting fixture 1000. The coolant circuit 570 may
then direct the fluid coolant 800 to the fluid circuits 700A and
700B, which may be used to heat the plurality of plants 900 and a
hot pool, respectively. The coolant circuit 570 may distribute and
direct heated fluid coolant 800 in a controlled manner by one or
valves 502 before the cooling tower 557 removes the remaining heat
in the fluid coolant 800.
[0126] In some implementations, the hydronics system 501 may also
be used to regulate the temperature of the ambient environment
itself. For example, the hydronics system 501 may be used to heat
the controlled agricultural environment 2000B convectively and/or
radiatively as the fluid coolant 800 flows through the hydronics
system 501 using a heat exchanger (not shown). Furthermore, it
should be appreciated that in other implementations, the CEH
systems may also eliminate the dehumidifier 65 as well. Thus, the
coolant circuit 570 may only pass through the lighting fixture 1000
and the fluid circuits 700A and 700B.
A Fluid-Cooled Lighting Fixture for a Close Proximity Grow
System
[0127] In some implementations, the controlled agricultural
environment and/or the CEH system may include a close proximity
grow system to provide high density cultivation of various crops
using limited space. The close proximity system may be
distinguished from other grow systems based on distance between the
lighting fixture and the plants, which may range between about 6
inches and about 72 inches. The close proximity grow system may
include, but is not limited to a racked CEH system (also referred
to as a "stacked CEH system" or a "shelved CEH system"), a vertical
CEH system (e.g., deployed in an urban environment such as the
interior of a building), an underwater CEH system (e.g., plants
grown in a tank of water, an ocean, or a fresh water source), and
any combination of the foregoing (e.g., a vertical CEH system
deployed underwater for algae or seaweed cultivation).
[0128] FIGS. 2A-2I show several views of an exemplary lighting
fixture 1000a that is configured for a close proximity grow system.
It should be appreciated, however, the lighting fixture 1000a may
also be deployed in other types of grow systems. As shown, the
lighting fixture 1000a may include a frame 1004 to provide
mechanical support for various components of the lighting fixture
1000a. For instance, FIGS. 2C-1 and 2C-2 show the frame 1004 may
support LED modules 410a-1, 410a-2, 410a-3, and 410a-4
(collectively referred to herein as LED modules 410a). Each of the
LED modules 410a may emit radiation (e.g., PAR) to illuminate one
or more plants in the CEH system. The frame 1004 may also support
control circuitry 90 (also referred to as the "processor 90") to
electrically power and control the LED modules 410a. The frame 1004
may include a coolant channel 1220 to support a coolant pipe 1006,
which carries a flow of fluid coolant (e.g., fluid coolant 800)
through the lighting fixture 1000a to dissipate the heat generated
by the LED modules 410a.
[0129] FIGS. 2A-2C-2 further show the lighting fixture 1000a may
include a tube 1300 defining a cavity 1302 to contain the frame
1004, the LED modules 410a, the control circuitry 90, and a portion
of the coolant pipe 1006. The tube 1300 may be transparent to the
radiation emitted by the LED modules 410a. The tube 1300 may
further include a first open end 1304a and a second open end 1304b.
A first end cap 1320a may be coupled to the tube 1300 and the frame
1004 to cover the first open end 1304a. Similarly, a second end cap
1320b may be coupled to the tube 1300 and the frame 1004 to cover
the second open end 1304b. As shown in FIGS. 2B-1 and 2B-2, the
coolant pipe 1006 may be routed and/or pass through the end caps
1320a and 1320b such that the respective ends of the coolant pipe
1006 protrude from the first and second end caps 1320a and 1320b.
Additionally, one or more electrical cables providing electrical
power and/or communication to the lighting fixture 1000a may be
coupled to a communication port (not shown) disposed on one or both
of the end caps 1320a and 1320b or routed through one or both of
the end caps 1320a and 1320b.
[0130] The combination of the tube 1300 and the end caps 1320a and
1320b may generally enclose and separate the frame 1004, the LED
modules 410a, the control circuitry 90, and a portion of the
coolant pipe 1006 from the surrounding environment. As a result,
the exterior dimensions of the lighting fixture 1000a may be
defined primarily by the dimensions of the tube 1300. In some
implementations, the cross-section of the tube 1300 may have an
exterior width of about 2 inches. In some implementations, the
length of the tube 1300 and, by extension, the lighting fixture
1000a may conform with standardized lengths of racks and/or rack
support structures in a vertical grow rack system. Thus, the length
of the tube 1300 may be about 48 inches or about 96 inches.
However, it should be appreciated the length of the tube 1300 may
generally range between about 48 inches and about 96 inches.
[0131] In some implementations, the tube 1300 may be dimensioned
such that the sides and/or edges of the tube 1300 do not physically
contact the frame 1004, the LED modules 410a, the control circuitry
90, and/or the portion of the coolant pipe 1006 (see, for example,
FIG. 2I). The tube 1300 may be further filled with air or gas
(e.g., argon, nitrogen), or may be evacuated. Thus, the air, gas,
or vacuum disposed between the sides of the tube 1300 and the
interior components of the lighting fixture 1000a, especially the
LED modules 410a, may act as a thermally insulating barrier that
reduces or, in some instances, eliminates heat dissipation to the
surrounding environment through the tube 1300.
[0132] In some implementations, the length and/or the weight of the
frame 1004 may be sufficiently large to cause the frame 1004 to sag
downwards (e.g., at its center point). To prevent the frame 1004
from contacting the tube 1300, the lighting fixtures 1000a may
include spacers (not shown) disposed at incremental distances along
the length of the frame 1004 to position the frame 1004 to reduce
or, in some instances, prevent physical contact between the frame
1004 and the tube 1300. The spacers may be shaped and/or
dimensioned to fit around at least a portion of the frame 1004 and
to physically contact the tube 1300. The spacer may be formed from
a thermally insulating material including, but not limited to,
polycarbonate and styrofoam to ensure the LED modules 410a remain
thermally insulated from the immediate surroundings around the tube
1300.
[0133] Generally, the tube 1300 may have various cross-sectional
shapes including, but not limited to, a circle, an ellipse, a
semi-circle, a polygon, and any combination of the foregoing. In
some implementations, the tube 1300 may preferably have a circular
cross-sectional shape (i.e., the tube 1300 may have a cylindrical
shape). The end caps 1320a and 1320b may also have a cylindrical
geometry to conform with the tube 1300. The smooth exterior surface
of a cylindrically shaped tube 1300 may make it easier to clean
and/or maintain the lighting fixture 1000a.
[0134] The cylindrical geometry of the tube 1300 may also allow the
lighting fixture 1000a to be coupled to a support structure (e.g.,
a rack structure) using standard commodity clamps, such as the
clamps 1370a and 1370b shown in FIGS. 10A and 10B. As shown, the
clamps 1370a and 1370b may be shaped to wrap around the tube 1300
and/or the end caps 1320a and 1320b and coupled to a rack structure
using a fastener inserted through the openings 1372 disposed on
opposing ends of the clamps 1370a and 1370b (i.e., the openings
1372 align to an opening on a rack structure). Alternatively, the
lighting fixture 1000a may be coupled to a support structure using
a zip tie 1370c as shown in FIG. 10C. Similar to the clamps 1370a
and 1370b, the zip tie 1370c may wrap around at least a portion of
the tube 1300 and/or the end caps 1320a and 1320b, fed through an
opening on rack, and subsequently tightened to secure the lighting
fixture 1000a to the rack.
[0135] The cylindrical geometry of the tube 1300 may also make the
lighting fixture 1000a more amenable to rotational and/or
translational adjustments after installation. For example, the
commodity clamps 1370a or 1370b may provide a small gap or
clearance with the tube 1300 such that the lighting fixture 1000a
is suspended above the plants while not being tightly constrained
(see, for example, FIG. 4B). This, in turn, may allow the tube 1300
and, by extension, the LED modules 410a to be rotated, for example,
about a longitudinal axis 1301 of the tube 1300 and/or slidably
displaced along the longitudinal axis 1301 so long as the clamps
1370a or 1370b remain in contact with the tube 1300 and/or the end
caps 1320a and 1320b.
[0136] More generally, the lighting fixture 1000a may be coupled to
a support structure via different coupling mechanism that provide
one or more degrees of freedom for adjustment including, but not
limited to a pin joint (e.g., a swivel joint clamp), a slider joint
(e.g., a rod or a pin mounted to the end caps 1320a and 1320b that
is disposed within a support structure with a slotted opening), and
any combinations of the foregoing. In some implementations, the
position and/or orientation of the lighting fixture 1000a may be
manually adjusted by a user or adjusted via a motor mechanically
coupled to the coupling mechanism and electronically
controlled.
[0137] Adjustments to the position and/or orientation of the
lighting fixture 1000a may provide several benefits to the
controlled agricultural environment.
[0138] First, the lighting fixture 1000a may illuminate different
sides and/or different portions of the plants. For example, the
position and/or orientation of the lighting fixture 1000a may be
continuously changed to simulate illumination by the sun during a
typical day cycle.
[0139] Second, the positional and/or rotational adjustment of the
lighting fixture 1000a may provide a mechanism to adjust the amount
or intensity of radiation illuminating the plants. For example, the
lighting fixture 1000a may be rotated towards or away from the
plants to increase or decrease, respectively, the intensity of the
radiation incident on the plants. It should be appreciated the
lighting fixture 1000a and, in particular, the control circuitry 90
may also include a dimmer to further adjust the intensity of the
emitted radiation incident on the plants as will be described in
more detail below.
[0140] Third, a CEH system may include an array of lighting
fixtures 1000a. If each lighting fixture 1000a is rotatably and/or
translationally adjustable, the lateral spacing and/or the relative
orientations between the lighting fixtures 1000a may be adjusted
after installation. This may allow the amount or the intensity of
the radiation incident on a particular growing area to be changed
and/or customized by combining the radiation emitted from multiple
lighting fixtures 1000a without having to disassemble and reinstall
the lighting fixtures 1000a. For example, it may be preferable to
increase the lateral spacing between the lighting fixtures 1000a to
reduce the intensity of the radiation when the plants are in a
vegetative growth stage. When the plants are in the flowering
growth stage, it may be preferable to decrease the lateral spacing
in order to increase the intensity of the radiation incident on the
plants. In another example, the growing area may include plants at
different stages of growth where some plants may be a seedling and
other plants may be fully matured and ready for harvesting. When a
plant is harvested, a new seedling may be planted in its place. The
position and/or orientation of the lighting fixtures 1000a may thus
be periodically adjusted to change the amount or the intensity of
the radiation incident on a particular portion of the growing area
(e.g., more radiation for more mature plants, less radiation for
less mature plants).
[0141] In some implementations, the tube 1300 may be formed and/or
extruded along a straight axis (e.g., the tube 1300 is shaped as a
right cylinder). In some implementations, the tube 1300 and/or the
cavity 1302 may be curved such that the first open end 1304a and
the second open end 1304b are not in parallel alignment. In some
implementations, the tube 1300 may have more than two open ends
(e.g., a Y-shaped tube, a X-shaped tube) and the frame 1004 and/or
the LED modules 410a may be disposed within different sections of
the tube 1300 accordingly.
[0142] As described above, the tube 1300 may be transparent to the
radiation emitted by the LED modules 410a as well as radiation
emitted by the plants or another object in the environment for
detection by a sensor and/or a camera integrated into the lighting
fixture 1000a. Generally, the tube 1300 may have a transmittance
greater than or equal to about 80% and, more preferably, greater
than or equal to 90% across various wavelength regimes including,
but not limited to, ultraviolet, visible, near-infrared,
mid-infrared, and long-infrared wavelength ranges. In some
implementations, the tube 1300 may be formed from a material with
sufficient mechanical strength to withstand a pressure difference
between the cavity 1302 and the environment of at least 1 atm
(e.g., if the tube 1300 is evacuated). The tube 1300 may be formed
from various materials including, but not limited to, glass (e.g.,
quartz), polycarbonate, acrylic, and polymethylmethacrylate
(PMMA).
[0143] FIGS. 2G and 2H show the frame 1004 in the lighting fixture
1000a may be a two-part assembly. Specifically, the frame 1004 may
include a first frame component 1200a to support the LED modules
410a and a second frame component 1200b to support the control
circuitry 90. It should be appreciated that, in other
implementations, the frame 1004 may be a single component that
supports both the LED modules 410a and the control circuitry
90.
[0144] Generally, the first frame component 1200a may span the
length of the tube 1300 and, hence, provide features to couple to
the end caps 1320a and 1320b. Thus, the coolant pipe 1006 may be
directly coupled to the first frame component 1200a. Therefore, in
some implementations, the first frame component 1200a may function
as a thermal conduit to conduct heat from the LED modules 410a to
the coolant pipe 1006. The first frame component 1200a may be
formed from various thermally conducting materials including, but
not limited to, aluminum, copper, stainless steel, and carbon
steel. In implementations where the LED modules 410a generates less
heat (e.g., more efficient LED's, the LED's emit lower intensity
radiation), the first frame component 1200a may be formed from
other various ceramics, polymers, and/or composites including, but
not limited to, polyethylene, acrylic, and porcelain.
[0145] The second frame component 1200b may be dimensioned and/or
shaped based on the geometry of the control circuitry 90. In some
implementations, the second frame component 1200b may be shorter
than the first frame component 1200a, thus only occupying a portion
of the cavity 1302 of the tube 1300. The second frame component
1200b may also electrically insulate, or, in some instances,
electrically isolate the control circuitry 90 from other components
of the lighting fixture 1000a, such as the first frame component
1200a. The second frame component 1200b may be formed from various
electrically insulating materials including, but not limited to,
plastic (e.g., polyethylene, polypropylene, polystyrene, PMMA).
[0146] Depending on the materials used to form the first frame
component 1200a and the second frame component 1200b, various
methods of manufacture may be utilized including, but not limited
to forming, extrusion, sandcasting, milling, injection molding, and
manual molding.
[0147] FIG. 3 shows a magnified view of the first frame component
1200a. As shown, the first frame component 1200a may have a first
side 1202a with a mounting channel 1204a to support the LED modules
410a. The mounting channel 1204a may be defined and/or flanked by
ridges 1206 on the first side 1202a. During assembly, the LED
modules 410a may be slidably positioned along the mounting channel
1204a and secured to the first frame component 1200a using, for
example, one or more zip ties 1210a that wrap around opposing ends
of each LED module 410a through openings 1214 formed in the first
frame component 1200a. FIGS. 2C-1 and 2C-2 show the LED modules
410a-1 through 410a-4 may each be disposed within the mounting
channel 1204a and evenly distributed along the length of the first
frame component 1200a. As will be discussed in more detail below,
the LED modules 410a may include a printed circuit board (PCB) 411
that may also be attached to the first frame component 1200a using,
for example, thermal paste.
[0148] The first frame component 1200a may also have a second side
1202b opposite the first side 1202a. Specifically, the first frame
component 1200a may include a pair of curved-shaped ribs 1216 that
extend downwards from a portion of the first side 1202a near the
mounting channel 1204a. The free ends of the ribs 1216 may define a
portion of the second side 1202b. The first frame component 1200a
may further include side ribs 1218 that extend downwards from the
ridges 1206 to define another portion of the second side 1202b. As
shown in FIGS. 2I and 3, the ends of the side ribs 1218 may each
define a mounting channel 1204b to support and/or slidably couple
to the second frame component 1200b.
[0149] The second frame component 1200b may be secured to the first
frame component 1200a using one or more mechanical coupling
mechanisms including, but not limited to, a zip tie, a screw
fastener, a bolt fastener, a clip, and a clamp. Additionally, the
mounting channels 1204b may provide openings that each receive a
fastener 1324 to couple the end caps 1320a and 1320b to the first
frame component 1200a. More generally, the end caps 1320a and 1320b
may be coupled to the frame 1004 using various coupling mechanisms
including, but not limited to, zip ties, screw fasteners, bolt
fasteners, clips, and clamps.
[0150] It should be appreciated that other electrical circuitry
associated with the control circuitry 90 may be coupled to the
first frame component 1200a. For example, FIG. 2F shows a power
board 91 directly mounted to the ribs 1216 via a zip tie 1210b. The
power board 91 may electrically connect together a port and/or an
electrical cable routed through the end caps 1320a or 1320b to the
control circuitry 90. In some implementations, the second frame
component 1200b may be positioned near one of the end caps 1320a or
1320b so that the control circuitry 90 may be directly connected to
an electrical port, an electrical cable routed through the end caps
1320a or 1320b, or the power board 91.
[0151] In some implementations, the first frame component 1200a may
also include an electrical feedthrough opening 1212 that extends
from the first side 1202a to the second side 1202b to provide a
pathway for electrical wiring to pass through the first frame
component 1200a and electrically couple together the LED modules
410a and the control circuitry 90. For example, FIGS. 2E and 2F
show the LED modules 410a and the control circuitry 90 may be
electrically coupled via an electrical wire 416 passing through the
electrical feedthrough opening 1212.
[0152] As shown in FIG. 3, the curved-shaped ribs 1216 may define a
coolant channel 1220 to secure the coolant pipe 1006 to the first
frame component 1200a. The coolant channel 1220 may be accessible
from the second side 1202b. The coolant channel 1220 may have a
cross-section that is shaped and/or dimensioned to conform with the
coolant pipe 1006 in order to increase the thermal contact area
between the coolant pipe 1006 and the first frame component
1200a.
[0153] The coolant pipe 1006 may be secured to the coolant channel
1220 of the first frame component 1200a using several
approaches.
[0154] For example, the cross-sectional dimensions of the coolant
channel 1220 may be equal to or smaller than the cross-sectional
dimensions of the coolant pipe 1006 to facilitate a press-fit
and/or a crush-fit where the coolant pipe 1006 is secured to the
channel via friction. In some implementations, the coolant pipe
1006 may be deformed when press-fit and/or crush-fit to the coolant
channel 1220 such that the coolant pipe 1006 does not protrude
outwards from the coolant channel 1220. For instance, FIG. 3 shows
the coolant pipe 1006 may have a flat side to provide clearance for
the second frame component 1200b.
[0155] In another example, the coolant pipe 1006 may be clamped to
the channel 1220 of the first frame component 1200a using, for
example, one or more clamps with zip ties and/or a worm drive
fastener. The clamps may be removable to allow replacement of the
coolant pipes 1006. The surface of the ribs 1216 forming the
coolant channel 1220 may also be polished to improve thermal
contact with the coolant pipe 1006, thus enabling greater heat
dissipation to the fluid coolant 800. Additionally, the coolant
pipe 1006 may be adhered or bonded to the first frame component
1200a using various methods including, but not limited to, adhesive
bonding, welding, and brazing. Thermal interface material may also
be disposed between the coolant channel 1220 and the coolant pipe
1006 to improve thermal contact.
[0156] The side ribs 1218 and the curved-shaped ribs 1216 may also
define side channels 1221 disposed on opposing sides of the coolant
channel 1220. The side channels 1221 may reduce the weight of the
first frame component 1200a and/or the amount of material used for
manufacture. Additionally, the side channels 1221 may also provide
a thermal barrier to reduce, or in some instances, prevent heat
from the LED modules 410a from being transferred to the second
frame component 1200b and, hence, the control circuitry 90. For
example, the side channels 1221 may contain air, gas, or a vacuum,
which may increase the thermal resistance between the first side
1202a and the second side 1202b.
[0157] Thus, the first frame component 1200a may be shaped such
that the heat generated by the LED modules 410a is transferred
primarily towards the coolant channel 1220 and the coolant pipe
1006. In some implementations, the coolant channel 1220 and the
coolant pipe 1006 may be disposed between the LED modules 410a and
the control circuitry 90 to further reduce or, in some instances,
prevent the transfer of the heat generated by the LED modules 410a
to the second frame component 1200b and the control circuitry
90.
[0158] In some implementations, the first frame component 1200a may
be formed via an extrusion process. Thus, the various structural
features of the first frame component 1200a (e.g., the ridges 1206,
the ribs 1218, 1216) may span the length of the first frame
component 1200a as shown in FIG. 3 to facilitate extrusion.
However, it should be appreciated the first frame component 1200a
may be formed using other manufacturing processes including, but
not limited to, casting, forging, and machining. When these other
manufacturing processes are used, these structural features may be
formed and/or span only a portion of the overall length of the
first frame component 1200a.
[0159] FIG. 2I shows the second frame component 1200b may include a
base 1223 that abuts the second side 1202b of the first frame
component 1200a. The second frame component 1200b may further
include rails 1226 that extend from the base 1223, which are shaped
and/or dimensioned to fit into the mounting channels 1204b of the
first frame component 1200a. For example, the rails 1226 may have a
thin stem section and a circular rod section disposed within the
mounting channel 1204b. Thus, the mounting channel 1204b may
constrain the rail 1226 to only slide along mounting channel
1204b.
[0160] The second frame component 1200b may further include sides
1224 extending from the base 1223 and away from the first frame
component 1200a with curved-shaped ridges 1225. The combination of
the ridges 1225, the sides 1224, the base 1223 may define a
mounting channel 1229 to support the control circuitry 90. As shown
the control circuitry 90 may include a PCB that may be inserted
into the mounting channel 1229 and constrained by the ridges 1225
clasping the edges of the PCB. Thus, the control circuitry 90 may
be inserted into the mounting channel 1229 and positioned as
desired along second frame component 1200b.
[0161] In some implementations, the control circuitry 90 may be
securely coupled to the second frame component 1200b using, for
example, one or more zip ties. In some implementations, the ridges
1225 may be shaped and/or dimensioned to impart a clamping force to
prevent the control circuitry 90 from moving relative to the second
frame component 1200b. For example, the clamping force may be
sufficiently large to prevent movement of the control circuitry 90
when the frame 1004 is tilted. However, the clamping force, may be
sufficiently small so that the user may still readily adjust the
position of the control circuitry 90 without having to apply an
appreciably large force.
[0162] The second frame component 1200b may also be formed by an
extrusion process; hence, the base 1223, sides 1224, and ridges
1225 may span the length of the second frame component 1200b.
Alternatively, the second frame component 1200b may be formed by an
injection molding process to produce the same or similar structural
features.
[0163] FIGS. 4A and 4B show the end cap 1320a (or the end cap
1320b) may be a two-part assembly that includes an end cap support
1350 to couple the end cap 1320a to the frame 1004 and an end cap
cover 1330 to cover the first open end 1304a of the tube 1300. The
end cap 1320b may similarly have an end cap support 1350 to couple
to the frame 1004 and an end cap cover 1330 to cover the second
open end 1304b of the tube 1300.
[0164] The end cap cover 1330 and the end cap support 1350 may
generally be formed from a thermally insulating material to reduce
or, in some instances, prevent the heat generated by the LED
modules 410a and transferred to the frame 1004 from dissipating
into surrounding environment through the end caps 1320a and 1320b
of the lighting fixture 1000a. The end cap support 1350 and the end
cap cover 1330 may also be non-corrosive and/or radio-wave
transparent (e.g., for wireless communication). In some
implementations, the end cap support 1350 may be formed from
various rigid plastics or polymers including, but not limited to,
polycarbonate and glass-filled polycarbonate. In some
implementations, the end cap cover 1330 may be formed from various
compliant plastics or polymers including, but not limited to,
urethane, rubber, and silicone. Depending on the materials used to
form the end cap support 1350 and the end cap cover 1330, various
methods of manufacture may be utilized including, but not limited
to, extrusion, injection molding, blow molding and manual
molding.
[0165] FIGS. 5A-5D show several views of the end cap support 1350.
As shown, the end cap support 1350 may include a base 1352 and
sidewalls 1351a and 1351b that protrude from the base 1352. The
base 1352 and the sidewalls 1351a and 1351b may generally be shaped
and/or dimensioned to conform with the geometry of the tube 1300.
For example, the base 1352 may have a circular shape to conform
with a cylindrically shaped tube 1300. As shown in FIG. 5B, the
sidewalls 1351a and 1351b may have cross-sectional shapes (i.e.,
the cross-section defined normal to the longitudinal axis 1301)
that trace different portions of a circular path 1358. For example,
the sidewall 1351a may trace out a top half portion of the circular
path 1358 and the sidewall 1351b may trace out a bottom portion of
the circular path 1358. The portions of the circular path 1358 that
are not covered by the sidewalls 1351a or 1351b may correspond to
notches 1353 formed between the sidewalls 1351a and 1351b. Said in
another way, the sidewalls 1351a and 1351b form different sections
of a cylindrically shaped, discontinuous sidewall separated by
notches 1353.
[0166] When the end cap support 1350 is coupled to the frame 1004,
the first frame component 1200a may be inserted between the
sidewalls 1351a and 1351b such that the side ribs 1218 may be
partially disposed in the notches 1353 and the end of the first
frame component 1200a physically contacts the base 1352 (e.g., the
mounting channels 1204a and 1204b contact the base 1352). In this
manner, the side ribs 1218 of the first frame component 1200a may
trace out the remaining portions of the circle 1358 corresponding
to the notches 1353.
[0167] The base 1352 may further include openings 1356 that align
with the channels 1204b of the first frame component 1200a as shown
in FIG. 5B. Thus, fasteners 1324 may be inserted through the
openings 1356 of the end cap support 1350 and coupled to the
channels 1204b of the first frame component 1200a as shown in FIGS.
2E and 2F. Additionally, the base 1352 may include a fluidic
feedthrough opening 1354 that aligns with the coolant channel 1220
so that the coolant pipe 1006 may pass through the end cap support
1350. The base 1352 may further include an electrical feedthrough
opening 1355 for an electrical cable to pass through the end cap
support 1350 and electrically couple to the control circuitry 90
and/or the power board 91. As shown in FIG. 5B, the electrical
feedthrough opening 1355 may be disposed along a top portion of the
base 1352 so that the electrical cable is positioned on the second
1202b of the first frame component 1200a where the control
circuitry 90 and the power board 91 are located.
[0168] When the end cap support 1350 is coupled to the tube 1300,
the curved exterior surfaces of the sidewalls 1351a and 1351b may
contact the interior curved surface of the tube 1300 and the first
open end 1304a of the tube 1300 may contact the base 1352 of the
end cap support 1350. Said in another way, the tube 1300 may be
supported by the exterior surfaces of the sidewalls 1351a and
1351b. Thus, the end cap support 1350 may couple to both the frame
1004 and the tube 1300. Furthermore, the end cap support 1350 may
position and align the tube 1300 relative to the frame 1004. In
some implementations, the exterior surfaces of the first frame
component 1200a and, in particular, the side ribs 1218 may not
extend past the exterior surfaces of the sidewalls 1351a and 1351b.
Thus, the end cap support 1350 may position the tube 1300 such that
the tube 1300 does not physically contact the frame 1004 and any
components coupled to the frame 1004 (e.g., the LED modules 410a,
the control circuitry 90, the coolant pipe 1006).
[0169] FIGS. 6A-6E show several views of the end cap cover 1330. As
shown, the end cap cover 1330 may include a sidewall 1331 and a
base 1332 that surround and partially enclose a cavity 1333.
Similar to the end cap support 1350, the sidewall 1331 and the base
1332 of the end cap cover 1330 may be shaped and/or dimensioned to
conform with the geometry of the tube 1300 (i.e., the cavity 1333
may be cylindrical in shape). The sidewall 1331 may generally have
an interior width that is approximately equal to the exterior width
of the tube 1300. In some implementations, the sidewall 1331 may
have tolerances that ensure the interior width of the sidewall 1331
is smaller than the exterior width of the tube 1300. In this
manner, the end cap cover 1330 may be stretched to fit onto the
exterior surface of the tube 1300 to form a tight seal with the
first open end 1304a of the tube 1300 and provide a clamping force
that clamps the tube 1300 between a recess 1322 formed between the
sidewall 1331 of the end cap cover 1330 and the sidewalls 1351a and
1351b of the end cap support 1350 as shown in FIG. 4B.
[0170] In some implementations, the end cap cover 1330 may be
clamped to the tube 1300 via a separate clamp (e.g., the commodity
clamp 1370a). The clamp 1370a, for example, may be tightened to
provide a sufficient clamping force to clamp and seal the end cap
cover 1330 to the tube 1300.
[0171] In some implementations, the end cap cover 1330 may be
formed from a heat-shrinkable material. Thus, when the end cap
cover 1330 is fitted onto the tube 1300 and/or the end cap support
1350, the end cap cover 1330 may be exposed to a heat source (e.g.,
a heat gun) to shrink and, hence, seal the cavity 1302 of the tube
1300 as well as the various electrical and fluidic connections
through the end caps 1320a and 1320b.
[0172] In some implementations, the end cap cover 1330 may form a
sufficiently tight seal with the tube 1300 to prevent foreign
substances (e.g., moisture, dust) in the environment from
infiltrating the cavity 1302. For example, the controlled
agricultural environment may operate at a relative humidity where
moisture may condense onto various surfaces of the lighting fixture
1000a. The accumulation of moisture may lead to damage of exposed
electrical devices, such as exposed electronic circuitry. The
combination of the tube 1300 and the end caps 1320a and 1320b may
thus provide an enclosure that substantially reduces or, in some
instances, prevents the infiltration of moisture and other foreign
substances into the cavity 1302.
[0173] In some implementations, the end cap cover 1330 may form a
water-resistant seal with the tube 1300 where water does not
infiltrate the cavity 1302 when the lighting fixture 1000a is
washed with water. In some implementations, the water-resistant
seal may also prevent water from infiltrating the cavity 1302 when
the lighting fixture 1000a is fully submerged underwater. In some
implementations, the end cap cover 1330 may form an airtight seal
with the tube 1300 (e.g., air from the environment does not
infiltrate the cavity 1302).
[0174] The end cap cover 1330 may additionally have several
features to facilitate electrical and fluidic connections to the
lighting fixture 1000a. For example, the base 1332 may include an
electrical feedthrough 1335 that defines an opening for an
electrical cable to pass through the end cap cover 1330 and into
the cavity 1302 of the tube 1300 for connection with the control
circuitry 90 and/or the power board 91. As shown in FIG. 6C, the
electrical feedthrough 1335 may be aligned with the electrical
feedthrough opening 1355 of the end cap support 1350. The
electrical feedthrough 1335 may include a sleeve that protrudes
outwards from the base 1332 and away from the end cap support 1350.
The sleeve may define a portion of the opening to receive the
electrical cable.
[0175] In some implementations, the sleeve may have an interior
width smaller than the exterior width of the electrical cable so
that when the electrical cable is inserted through the end cap
cover 1330, the sleeve may stretch, thus forming a tight seal with
the electrical cable. In some implementations, the sleeve may form
a water-resistant seal with the electrical cable. In some
implementations, the portion of the sleeve joined to the electrical
cable may be sealed using a sealant.
[0176] In another example, the base 1332 may include a fluidic
feedthrough 1334 that defines an opening for the coolant pipe 1006
to pass through the end cap cover 1330. The fluidic feedthrough
1334 may be aligned with the fluidic feedthrough opening 1354 of
the end cap support 1350. Similar to the electrical feedthrough
1335, the fluidic feedthrough 1334 may include a sleeve that
protrudes outwards from the base 1332 and away from the end cap
support 1350. The sleeve may also define a portion of the opening
to receive the coolant pipe 1006.
[0177] In some implementations, the sleeve of the fluidic
feedthrough 1334 may have an interior width smaller than the
exterior width of the coolant pipe 1006 so that when the coolant
pipe 1006 is inserted through the end cap cover 1330, the sleeve
may stretch, thus forming a tight seal with the coolant pipe 1006.
In some implementations, the sleeve may form a water-resistant seal
with the coolant pipe 1006. In some implementations, the portion of
the sleeve joined to the coolant pipe 1006 may be sealed using a
sealant.
[0178] The end cap cover 1330 may further include one or more
fastener cover sections 1336 disposed on the base 1332. The
fastener cover sections 1336 may be recessed portions of the base
1332 when facing towards the end cap support 1350 (or protruding
portions of the 1332 when facing away from the end cap support
1350). The fastener cover sections 1336 may provide space to cover
the fasteners 1324 that couple the end cap support 1350 to the
first frame component 1200a, particularly if the heads of the
fasteners 1324 protrude from the base 1352 of the end cap support
1350.
[0179] In some implementations, the end cap cover 1330 may not be
directly coupled to the end cap support 1350. Instead, the end cap
cover 1330 may be stretched and placed over the tube 1300 and the
base 1352 of the end cap support 1350 to enclose the first open end
1304a of the tube 1300 as described above. In some implementations,
the end cap cover 1330 may remain coupled to the tube 1300 and/or
the end cap support 1350 via the frictional force that arises
between the end cap cover 1330 and the tube 1300. In some
implementations, a zip tie or another clamping mechanism may be
disposed around the end cap cover 1330 to securely couple the end
cap cover 1330 to the tube 1300.
[0180] Mechanically decoupling the end cap cover 1330 from the end
cap support 1350 in this manner may have several benefits.
[0181] First, the end cap cover 1330 may be coupled to the tube
1300 and/or the end cap support 1350 without any additional
components (e.g., fasteners), thus simplifying assembly and
reducing the number of parts in the lighting fixture 1000a.
[0182] Second, the compliance of the end cap cover 1330 may allow
the tube 1300 and the frame 1004 to move relative to each other
while maintaining a tight seal with the tube 1300 and, hence,
keeping the cavity 1302 of the tube 1300 enclosed.
[0183] For example, the frame 1004 and, in particular, the first
frame component 1200a may thermally expand due to the heat
generated by the LED modules 410a during operation of the lighting
fixture 1000a. FIG. 4C shows an end portion of the lighting fixture
1000a where the first frame component 1200a is at a first
temperature (e.g., room temperature) before the LED modules 410a
are turned on. As shown, the tube 1300 may initially abut the base
1352 of the end cap support 1350 when the first frame component
1200a. Additionally, the end cap support 1350 may be rigidly
coupled to the first frame component 1200a via the fastener 1324
and the end cap cover 1330 may cover the exterior portions of the
end cap support 1350 and a portion of the tube 1300.
[0184] FIG. 4D shows the end portion of the lighting fixture 1000a
where the first frame component 1200a is heated to a second
temperature greater than the first temperature after the LED
modules 410a are turned on. As shown, the overall length of the
first frame component 1200a may increase due to thermal expansion,
which causes the end of the first frame component 1200a and the end
cap support 1350 to be displaced by a distance .DELTA.L. However,
rather than subjecting the tube 1300 to a tensile force (i.e., if
the tube 1300 is rigidly coupled to the end cap support 1350), the
curved interior surface of the tube 1300 may instead slide along
the curved exterior surfaces of the sidewalls 1351a and 1351b of
the end cap support 1350 as the end cap support 1350 is displaced.
In this manner, the displacement of the first frame component 1200a
and the end cap support 1350 reduces or, in some instances,
mitigates any undesirable forces applied to the tube 1300.
Furthermore, the end cap cover 1330 may be deformed to accommodate
the displacement of the end cap support 1350 while remaining
coupled to the tube 1300, thus keeping the cavity 1302
enclosed.
[0185] As described above, the coolant pipe 1006 may carry a flow
of fluid coolant 800 to capture the heat generated by the LED
modules 410a. The coolant pipe 1006 may generally have a length
longer than the frame 1004 so that respective end portions of the
coolant pipe 1006 extend beyond the frame 1004 and through the end
caps 1320a and 1320b as shown in FIGS. 2B-1 and 2B-2. In this
manner, the coolant pipe 1006 may be fluidically coupled to other
piping systems in a CEH system (e.g., another coolant pipe 1006 of
another lighting fixture 1000a, the pipes of a fluid coolant
circuit in a hydronics system) using, for example, an intermediate
pipe or a compliant hose.
[0186] The coolant pipe 1006 may generally be coupled to another
pipe or hose using various coupling mechanisms including, but not
limited to, threaded fittings (e.g., the ends of the coolant pipe
1006 have corresponding threads), bolt fasteners (e.g., the end of
the coolant pipe 1006 has a flange that mates to a corresponding
flange on another pipe), and push-to-connect plumbing fittings
(e.g., the ends of the coolant pipe 1006 are left bare).
Push-to-connect plumbing fittings may be preferable since the
piping connections do not include internal seals and/or O-rings,
thus simplifying the design and installation of the lighting
fixture 1000a.
[0187] The coolant pipe 1006 may generally be formed from various
materials including, but not limited to, copper, aluminum, and
stainless steel. In some implementations, the coolant pipes 1006
may be preferably formed from copper to reduce algae growth,
fouling, and/or corrosion. In some implementations, the various
pipes in the CEH system may be formed from copper and/or the
interior surfaces of the hoses may be coated with copper. In some
implementations, the coolant pipe 1006 may be coated or plated with
nickel. When push-to-connect plumbing fittings are used, the fluid
coolant 800 may thus pass through a fluid coolant circuit made only
of copper. In other words, the fluid coolant 800 does not contact
other materials in the lighting fixture 1000a (e.g., the frame
1004).
[0188] The cross-sectional dimensions of the coolant pipe 1006 may
vary depending on several factors including, but not limited to, a
desired flow rate, fluid coolant properties (e.g., dynamic
viscosity, density), and a desired type of flow. For example, it
may be desirable for the fluid coolant to be in a turbulent flow
regime, which may yield a higher heat transfer coefficient, thus
dissipating more heat from the lighting fixture 1000a. In some
implementations, the cross-sectional dimensions of the coolant pipe
1006 may be chosen such that the Reynold's number (Re) is greater
than a desired threshold (e.g., Re>4000 for turbulent flow) for
a given pump power and coolant circuit layout. In some
implementations, the coolant pipe 1006 may have an exterior width
of about 0.5 inches.
[0189] In some implementations, the interior surface of the coolant
pipe 1006 may also be roughened to increase the surface area and,
hence, the convective heat transfer coefficient to further increase
the cooling rate. The effective depth and pitch of the interior
surface roughness may be chosen to reduce or, in some instances,
prevent large increases to the pumping power (e.g., due to a larger
pressure drop) and maintain wettability of the interior surface of
the coolant pipe 1006 to the fluid coolant 800 (e.g., remains
hydrophilic, oleophilic).
[0190] The fluid coolant 800 used to capture and carry heat from
the lighting fixture 1000a may be chosen based on several factors.
First, the fluid coolant 800 may have a high thermal conductivity
and a high specific heat to increase the rate at which heat
generated by the LED modules 410a is transferred and stored in the
fluid coolant 800. Second, the fluid coolant 800 should preferably
remain in a liquid phase within the operating temperature and
pressure range of the controlled agricultural environment. For
example, the fluid coolant 800 should not freeze or boil as it
passes through the lighting fixture 1000a and/or any other
components disposed along the fluid coolant circuit of the
hydronics system (e.g., the heat rejection device, the pumps).
Third, the fluid coolant 800 may be chosen based on the materials
used in the construction of the fluid coolant circuit and, in
particular, the coolant pipe 1006 of the lighting fixture 100a. For
example, the fluid coolant 800 should preferably avoid corroding
the coolant pipe 1006. In some implementations, the fluid coolant
800 may thus be various fluids including, but not limited to,
water, mineral oil, glycol, and mixtures of any of the
foregoing.
[0191] The LED modules 410a may each include one or more LED light
sources (also referred to herein as LED elements) arranged into an
array. Each LED light source may emit light or, more generally,
radiation with a narrow wavelength band (e.g., a LED emits
radiation based on the band gap of a semiconductor, such as blue,
green, or red light) or a broad wavelength band (e.g., a LED
includes a phosphor to emit a broad spectrum of radiation, such as
white light). Thus, an array that includes multiple, different LED
light sources may provide radiation that covers a broad spectrum
(e.g., from ultraviolet (UV) wavelengths to infrared wavelengths)
and a spectral intensity distribution (i.e., the intensity of
radiation at different wavelengths or wavelength bands) that may be
dynamically tuned based on user preferences (e.g., changing the
proportion of red light or blue light incident on the plants).
[0192] Generally, the radiation emitted by the LED light sources
may be used in several ways in the controlled agricultural
environment including, but not limited to, providing photosynthetic
active radiation (PAR) to increase photosynthetic activity in the
plants, using radiation at different wavelengths to modify the
growth of plants (e.g., using radiation to modulate the day-night
cycle of plants), UV sterilization (e.g., to repel pests), and
sensing (e.g., illuminating the plants using radiation at different
wavelengths for the purposes of acquiring spectral or hyperspectral
imagery).
[0193] The LED light sources may emit radiation in various
wavelength regimes including, but not limited to, UV, visible,
near-infrared (NIR), and short wavelength infrared (SWIR). In some
implementations, one or more of the LED light sources may be
essentially monochromatic LED elements that emit radiation at
various wavelengths including, but not limited to, 275 nm, 365 nm,
440 nm, 450 nm, 475 nm, 500 nm, 530 nm, 620 nm, 630 nm, 660 nm, 696
nm, 730 nm, 760 nm, 850 nm, 860 nm, 940 nm, 950 nm, 1450 nm, 1610
nm, and 2060 nm. In some implementations, one or more of the LED
light sources may be broadband LED elements that emit radiation
across one or more wavelength regimes including, but not limited
to, UV, visible, NIR, SWIR, and any combinations of the
foregoing.
[0194] In one example, FIG. 2A shows the LED modules 410a may each
include a printed circuit board (PCB) 411 supporting multiple LED
light sources. Specifically, FIGS. 2A and 2E show the LED module
410a may include a LED light source 412a that provides white light
(e.g., radiation at an equivalent black body temperature of 5000K)
and a LED light source 412b that provides red light (e.g., 660 nm).
The LED light sources 412a and 412b may be collectively referred to
herein as the LED light sources 412. The LED module 410a may
further include one or more electrical connectors 414 to
electrically couple the LED module 410a to the control circuitry
90. For example, the electrical wire 416 may couple to the
electrical connector 414 of the LED module 410a.
[0195] In general, the number of LED light sources 412 may vary
based, in part, on the desired radiation output and/or intensity at
one or more wavelength bands. For example, the LED module 410a may
include a relatively larger number of LED light sources 412a to
provide more full-spectrum PAR and a relatively smaller number of
LED light sources 412b sufficient to induce desired photochemical
and/or photosynthetic activity in the plants (e.g., making the
plants feel as if it is being directly illuminated with
sunlight).
[0196] In some implementations, the LED light sources 412 may be
distributed across the lighting fixture 1000a to provide
substantially uniform or uniform illumination at the respective
wavelengths or wavelength bands of radiation emitted by the
different types of LED light sources 412. However, it should be
appreciated that, in other implementations, the LED light sources
412 may be non-uniformly distributed in the lighting fixture 1000a
(e.g., LED light sources 412a may be disposed at one end of the
lighting fixture 1000a and LED light sources 412b may be disposed
at an opposite end of the lighting fixture 1000a). For example,
each type of LED light source may be grouped together to provide a
higher intensity of radiation at a particular wavelength or
wavelength band. Additionally, the position and/or orientation of
the lighting fixture 1000a may be dynamically adjusted during
operation so that the plants may uniformly receive the higher
intensity radiation.
[0197] In some implementations, one or multiple LED light sources
412 in each LED module 410a may be separately controlled. For
example, the control circuitry 90 may control the amount of
electrical power delivered to each individual LED light source 412
so that radiation output from each LED light source 412 is tunable.
In another example, the control circuitry 90 may control LED light
sources 412 of the same type (e.g., turning on or off the white LED
light sources 412a separately from the red LED light sources 412b).
In some implementations, the control circuitry 90 may control each
LED module 410a separately from other LED modules 410a (e.g.,
turning on or off the LED module 410a-1 while adjusting the
radiation output of the LED module 410a-2).
[0198] In some implementations, the PCB 411 may be a metal core
printed circuit board (MCPCB) to dissipate the heat generated by
the LED light sources 412 more effectively (e.g., the heat is more
readily spread across the PCB 411). The LED module 410a may be
coupled to the first frame component 1200a such that the backside
of the PCB is in contact with the bottom surface of the mounting
channel 1204a. As described above, the LED module 410a may be
coupled to the first frame component 1200a using a zip tie 1210a.
Additionally, the LED modules 410a may be coupled to the first
frame component 1200a using an adhesive and/or a thermal interface
material (e.g., thermal paste) to provide greater thermal contact
with the first frame component 1200a (e.g., placing the thermal
paste between the PCB 411 and the first frame component 1200a).
[0199] More generally, the LED modules 410a may be coupled to the
first frame component 1200a using various coupling mechanisms
including, but not limited to, screw fasteners, bolt fasteners,
clips, adhesives, and clamps. In some implementations, the coupling
mechanism may provide an adjustable clamping force applied to the
LED modules 410a to increase, for example, the thermal contact
between the LED modules 410a and the first frame component
1200a.
[0200] FIGS. 7A-7E show several views of another exemplary LED
module 410b with four rows of LED light sources 412. Similar to the
LED module 410a, the LED module 410b may include a PCB 411 to
support the array of LED light sources 412. Electrical connectors
414 may also be disposed at opposing ends of the PCB 411 for
connection with the control circuitry 90 via one or more wires 416.
As shown, the LED light sources 412 may be uniformly distributed
across the PCB 411 to provide uniform illumination of the plants.
As shown in FIG. 7B, the LED module 410b may have a length of about
19.5 inches and a width of about 1.063 inches.
[0201] FIGS. 8A-8E show several views of another exemplary LED
module 410c that is smaller than the LED module 410b. As shown, the
LED module 410c may include two rows of LED light sources 412
supported by a PCB 411 with electrical connectors 414 disposed at
opposing ends of the PCB 411 for connection with the control
circuitry 90 via one or more wires 416. FIG. 8B shows the LED
module 410b may have a length of about 9.5 inches and a width of
about 0.63 inches.
[0202] The number of LED modules included in the lighting fixture
1000a may depend, in part, on the dimensions of each LED module.
For example, the lighting fixture 1000a may include a larger number
of LED modules 410c than the LED modules 410b. This may allow for
lighting fixtures 1000a to have different LED modules with
different distributions and/or types of LED light sources to
customize the spectral content and intensity of the radiation
provided by the lighting fixture 1000a. It should be appreciated
that so long as the LED modules fit within the mounting channel
1204a, the LED module may still be installed on the first frame
component 1200a even if the LED module is smaller in size than the
mounting channel 1204a. For example, the LED module 410c may still
be coupled to the first frame component 1200a using a combination
of zip ties 1210a and/or thermal paste/adhesive.
[0203] In some implementations, the lighting fixture 1000a may also
include an optic (not shown) disposed on the tube 1300 or within
the cavity 1302. In some implementations, one or more optics may be
mounted directly onto the LED modules 410a. The optic may be used
to modify the direction and/or the angular distribution of the
light emitted by the LED modules 410a. For example, a portion of
the optic may have a convex surface to focus light emitted from the
LED module 410a onto plants located directly below the lighting
fixture 1000a. The optic may be coupled to the frame 1004 and, in
particular, the first frame component 1200a, using various coupling
mechanisms including, but not limited to screw fasteners, bolt
fasteners, clips, and clamps.
[0204] In some implementations, the lighting fixture 1000a may
include one or more alert indicators. The alert indicator may
generally be a visual and/or audio alert. For example, FIG. 2C-2
shows the lighting fixture 1000a may include a visual alert
indicator 1240 disposed on the first frame component 1200a near the
end cap 1320a. The alert indicator may generally provide a user an
alert notification regarding the operating status of the lighting
fixture 1000a. For example, if the lighting fixture 1000a is
operating normally, the alert indicator 1240 may emit green light.
If the lighting fixture 1000a is overheating, the alert indicator
1240 may emit red light. If the operation of the lighting fixture
1000a is interrupted or not functioning properly, the alert
indicator 1240 may emit yellow light. Generally, the alert
indicator 1240 may be activated for various conditions including,
but not limited to, the lighting fixture 1000a overheating, the
control circuitry 90 no longer functioning properly (e.g., the
control circuitry 90 has stopped), the LED modules 410a do not emit
radiation when the lighting fixture 1000a receives power and is
commanded to emit radiation, the lighting fixture 1000a is at too
low of an operating temperature, and the lighting fixture 1000a is
receiving power, but is not operating as desired.
[0205] The control circuitry 90 may generally provide several
functions to facilitate the operation of the lighting fixture 1000a
including, but not limited to, power conversion (e.g., conversion
of AC power to DC power for the LED modules 410a), network
connectivity (e.g., communication with other sensor(s) or control
system(s) in the controlled agricultural environment), data
processing (e.g., receiving sensory data from sensors coupled to
the lighting fixture 1000a and adjusting an operational parameter
of the lighting fixture 1000a without receipt of instructions from
another system), control of the LED modules 410a (e.g., adjusting
the radiation intensity), and control of auxiliary devices coupled
to the lighting fixture 1000a (e.g., sensors, cameras). In some
implementations, the control circuitry 90 may additionally include
a dimmer or dimming functionality that controllably reduces the
radiation output of the LED modules 410a or each LED light source
412. For example, each LED light source 412 may emit radiation at a
nominal intensity (with the dimmer deactivated), which may be
decreased to 1% of the nominal intensity via the dimmer.
[0206] Various sensors and/or cameras may be integrated into the
lighting fixture and/or communicatively coupled to the lighting
fixture including, but not limited to, a light temperature sensor
to monitor the temperature of the LED module(s), a cold-side fluid
coolant temperature sensor to measure the temperature of the fluid
coolant entering the coolant pipe of the lighting fixture, a
hot-side fluid coolant temperature sensor to measure the
temperature of the fluid coolant exiting the coolant pipe of the
lighting fixture, an ambient air temperature sensor, a relative
humidity sensor, a carbon dioxide sensor, an air speed sensor, a
light sensor (visible, UV, near-infrared, short
wavelength-infrared, long wavelength-infrared), LiDAR, and a camera
(visible, UV, near-infrared, short wavelength-infrared, long
wavelength-infrared).
[0207] The control circuitry 90 may be electrically coupled to an
electrical cable or cable assembly that provides electrical power
and/or communication to the lighting fixture 1000a. In some
implementations, the control circuitry 90 may be configured to
receive AC power greater than or equal to about 175 W (e.g., 350
W). The power density, which is defined as the ratio of the
electrical power input to the exterior length of the lighting
fixture, the volume of the lighting fixture, and/or the volume of
the grow space. If the tube 1300 is cylindrical in shape with a
diameter of 2 inches and a length of 96 inches, the power density
per unit length of the lighting fixture may be about 1.8 W per
inch. The power density per unit volume of the lighting fixture may
be about 0.6 W per cubic inches (e.g., 175 W divided by .pi.(2
inches).sup.2/4(96 inches)). If the grow space is assumed to be a
cube with 3.27 foot (i.e., 1 m) long sides, the power density per
unit volume of the grow space may be about 5 W per cubic feet. More
generally, the lighting fixture 1000a may have a power density per
unit length of the lighting fixture greater than or equal to about
1.5 W per inch, a power density per unit volume of the lighting
fixture greater than or equal to about 0.5 W per cubic inches,
and/or a power density per unit volume of the grow space greater
than or equal to about 5 W per cubic feet.
[0208] In some implementations, the control circuitry 90 may be
comprised of discrete electronics assemblies that are electrically
coupled together and disposed on one or more PCB's. For example,
FIGS. 9A-9E show several views of the control circuitry 90 in the
lighting fixture 1000a. As shown, the control circuitry 90 may
include numerous electronic elements disposed on a single PCB 92.
In general, the PCB 92 may be shaped and/or dimensioned based on
the geometry of the tube 1300 and/or the frame 1004. For example,
the PCB 92 may be rectangular in shape to conform with the geometry
of the second frame component 1200b. FIG. 9B further shows the PCB
92, in some implementations, may have a length of about 20.5 inches
and a width of about 1.65 inches. The various electronic elements
disposed on the PCB 92 may also be arranged and/or dimensioned
based on the spatial constraints imposed by the tube 1300. For
example, FIG. 9E shows the electronic elements may not extend
beyond about 0.7 inches from the PCB 92.
[0209] The various electronics assemblies may provide one or more
distinct functions to the control circuitry 90. For example, FIG.
11A shows a block diagram of the various electronic components and
circuitry in the control circuitry 90 and their functions. FIGS.
11B-1 through 11B-4 show four portions of a circuit diagram
corresponding to the block diagram of the control circuitry 90 in
FIG. 11a. As shown, the control circuitry 90 may regulate and
distribute electrical power to other components of the lighting
fixture 1000a. In terms of the inputs and/or outputs of the control
circuitry 90, FIG. 11A shows the control circuitry 90 may receive
AC power through an electrical power port 1010, which may be
converted to DC power. The control circuitry 90 may then supply the
DC power and other control signals to other electronics in the
lighting fixture 1000a (e.g., the LED modules 410a, auxiliary
devices communicatively coupled to the lighting fixture 1000a,
sensors integrated into the lighting fixture 1000a). For example,
the control circuitry 90 may be directly coupled to multiple LED
modules 410a via corresponding ports/connectors in the control
circuitry 90 (e.g., the LED board ports 104A, 104B, and 104C if the
lighting fixture 1000a has only three LED modules 410a).
[0210] The control circuitry 90 may also be electrically and
communicatively coupled to a separate communications board (not
shown) via a communications board port 173, which provides power
and data communication to the communications board. In some
implementations, the communications board may manage data
communication between various devices coupled to the lighting
fixture 1000a including, but not limited to, other lighting
fixtures 1000a, one or more auxiliary sensors coupled to the
lighting fixture 1000a, and one or more external communications
devices (WiFi, Bluetooth, RS-485). In some implementations, the
communications board port may be used to supply electrical power at
different voltages, e.g., 48 V and 5 V, to the communications
board.
[0211] FIG. 11A further shows the control circuitry 90 may include
a fuse 170 as a safety feature to protect the various electronics
of the control circuitry 90 from overcurrent. In some
implementations, the control circuitry 90 may be configured to work
with a power line carrier (PLC) in which electrical power and data
communication are carried on the same conductor. The control
circuitry 90 may include an electrical power coupler 171 to
separate the communication signals from the electrical power
received by the PLC.
[0212] For power conversion, the control circuitry 90 may include
an electromagnetic interference (EMI) filter 153 to reduce noise
input and a rectifier 157 to convert AC power to DC power. An AC
line sensor 155 may be electrically coupled to the output of the
rectifier 157 to monitor the voltage and current of the DC power.
The DC power may be transmitted to a bias and control power supply
156, which may distribute DC power to other components of the
lighting fixture 1000a including the communications board and a
digital signal processor (DSP) 150. A DC-DC converter (not shown)
may also be included to supply different voltage inputs to other
electrical circuits coupled to the control circuitry 90 (e.g., a
communications board). For data communication, the control
circuitry 90 may include a PLC module 172 to extract and interpret
communication signals carried on the PLC.
[0213] As shown, the PLC module 172 and the bias and control power
supply 156 may be connected to the DSP 150 to provide communication
signals (e.g., commands, data) and power, respectively. The DSP 150
may also receive a voltage and current measurement from the AC line
sensor 155, and LED board sensor inputs via the sensor ports 157a,
which may be used, but not limited to, monitoring the temperature
of the LED modules 410a. The DSP 150 may provide control signals by
executing firmware 152 to various components including the
communications board. The control circuitry 90 may include onboard
memory, in which control and digital signal processing (DSP)
firmware 152 is stored to facilitate generation of control signals.
The DSP 150 may also provide control signals to one or more boost
converters (e.g., boost converters 162A, 162B, and 162C if three
LED modules 410a are included in the lighting fixture 1000a), which
may be used to regulate electricity supplied to the LED modules via
the LED board ports. The boost converters may also receive DC power
directly from the rectifier 157 as well.
[0214] In some implementations, the control circuitry 90 may manage
the voltage and current supplied to various components of the
lighting fixture 1000a (e.g., the LED modules 410a) in order to
reduce the likelihood of damage under different operating
conditions. For example, the lighting fixture 1000a may operate
under low voltage conditions where at least about 175 W may be
supplied to the LED modules 410a and at least about 25 W for any
auxiliary sensors and/or other devices coupled to the lighting
fixture 1000a. In some implementations, the electrical cable
coupled to the lighting fixture 1000a to supply power from an
external source, e.g., a building electrical supply system or
electrical mains, may be rated to sustain a current up to 30 A.
[0215] The control circuitry 90 may limit the current through the
lighting fixture 1000a to a lower current (e.g., 5 A (or 10 A) for
three LED modules 410a) such that the lighting fixture 1000a may be
powered by a single electrical cable. If the current draw of the
lighting fixture 1000a approaches 5 A (or 10 A), the control
circuitry 90 may reduce the power draw of the lighting fixture
1000a. In this manner, the three LED modules 410a may collectively
avoid a total current draw that exceeds 15 A (or 30 A), thus
reducing the likelihood of damaging the electrical cable.
[0216] In some implementations, the control circuitry 90 may
enforce a current draw limit using an active feedback control loop.
For example, the DSP 150 of the control circuitry 90 may actively
measure the voltage and/or current supplied to the lighting fixture
1000a via the AC line sensor 155. Depending on the magnitude and/or
rate of change of the measured voltage and current, the DSP 150 may
adjust the voltage and current supplied to each of the LED modules
410a such that the current drawn by the lighting fixture 1000a is
maintained below the current draw limit.
[0217] This process may be conducted in an iterative manner where
measurements of the voltage and current supplied to the lighting
fixture 1000a and subsequent adjustments to the voltage and current
supplied to the LED modules 410a repeatedly occur at a preset
timescale. In some implementations, the timescale may vary from
about 1 ms to about 60 s. The amount the voltage and current are
varied during each increment may also vary according to the rate of
change of the voltage and current supplied to the lighting fixture
1000a. In some implementations, the stability of the active
feedback control loop may be controlled by incorporating a
proportional integral differential (PID) controller into the
control circuitry 90.
[0218] FIGS. 12A-121 show exemplary circuit diagrams corresponding
to the various electrical components of the control circuitry 90.
FIG. 12A shows circuit diagrams for the electrical power port 1010,
fuse/EMI filter 153, a rectifier 154, and a first portion of a bias
and control power supply 156. FIG. 12B shows a second portion of
the bias and control power supply 156 shown in FIG. 12A. FIGS.
12C-12F show an optional DC-DC converter 158, an AC line sensor
155, a DSP 150, and a temperature sensor 173. FIGS. 12G and 12H
show circuit diagrams of an exemplary boost circuit 162A in the
control circuitry 90. FIG. 12I shows circuit diagrams for the
electrical power coupler 171 and the PLC module 172.
[0219] As described above, one or both of the end caps 1320a and
1320b may include an electrical feedthrough (e.g., electrical
feedthrough 1335, electrical feedthrough opening 1355) to route an
electrical cable into the cavity 1302 of the tube 1300 for
electrical connection with the control circuitry 90 and/or the
power board 91. In some implementations, the lighting fixture 1000a
may instead have one or more power/communication ports disposed on
one or both of the end caps 1320a and 1320b to receive and/or
transmit power and/or data communication. The power/communication
ports may be various types of ports including, but not limited to,
a Power Line Carrier (PLC), RS-485, Power over Ethernet (PoE),
Universal Serial Bus (USB), WiFi, and Bluetooth ports. FIGS.
15A-15C show several examples of a lighting fixture 1000a with
different communication ports (a RS-485 port 1337a, a USB port
1337b, a PoE port 1337c) disposed on the end cap 1320a.
[0220] For example, the lighting fixture 1000a may include a power
port to supply auxiliary DC power to one or more auxiliary devices
coupled to the lighting fixture 1000a, such as a sensor or camera,
or another lighting fixture 1000a. In another example, the lighting
fixture 1000a may include a communications port to transmit various
signals (e.g., commands, data) to and/or from the auxiliary devices
(e.g., the sensor or camera, another lighting fixture 1000a). In
another example, the lighting fixture 1000a may include a combined
power and communications port to receive electrical power and/or
transmit various signals (e.g., a PLC port).
[0221] The lighting fixture 1000a may receive various signals and
the control circuitry 90 may adjust various operating parameters
based on the signals including, but not limited to, adjustments to
electrical power (e.g., high voltage and low voltage modes),
adjustments to the total or spectral intensity of radiation emitted
by the LED modules 410a, turning on or off the LED modules 410a,
adjusting the rate at which the intensity of radiation changes in
the LED modules 410a, adjustments to the spectral content of the
emitted radiation (e.g., directing more power to blue or red LED
elements), requests for lighting fixture conditions, and commands
to operate auxiliary sensor devices (e.g., frequency of data
recording). The lighting fixture 1000a may also send or transmit
various status and monitoring including, but not limited to,
operating status or mode, electrical power consumption,
temperature, and data measured by internal or auxiliary sensor
devices.
[0222] FIGS. 13A-1-13E show several views of another lighting
fixture 1000b. Similar to the lighting fixture 1000a, the lighting
fixture 1000b may include a frame 1004 to support one or more LED
modules 410d and control circuitry 90. The frame 1004 may further
support a coolant pipe 1006 to cool the LED modules 410d during
operation. The lighting fixture 1000b may further include a tube
1300 with respective ends covered by end caps 1320a and 1320b
(note: only the end cap supports 1350 are shown).
[0223] The combination of the tube 1300 and the end caps 1320a and
1320b may once again provide an enclosure to contain the frame
1004, the LED modules 410d, the control circuitry 90, and a portion
of the coolant pipe 1006. In this example, the end cap 1320b may
include an electrical feedthrough opening 1355 with a threaded
connector 1157 to securely couple an electrical cable to the
lighting fixture 1000b. The electrical cable may be routed through
the electrical feedthrough opening 1355 and secured via the
threaded connector 1157. The threaded connector 1157 may also
support a power and/or communications port to couple the electrical
cable to the lighting fixture 1000b.
[0224] FIG. 13E shows the frame 1004 may include a first frame
component 1200a and a second frame component 1200b. The first frame
component 1200a may provide a mounting channel 1204a on a first
side 1202a to support the LED modules 410d. As before, the mounting
channel 1204a may be defined, in part, by the ridges 1206a. In this
example, the mounting channel 1204a may be shaped and/or
dimensioned such that wedges 1230 may be disposed and coupled to
the ridges 1206a to press and secure the LED module 410d to the
first frame component 1200a, in part, to increase thermal contact.
The wedge(s) 1230 may be mechanically compliant components.
[0225] The first frame component 1200a may further include a second
side 1202b with ridges 1206b that define, in part, a mounting
channel 1204c to couple to a second frame component 1200b carrying
the control circuitry 90. The second frame component 1200b may be
slidably coupled to the mounting channel 1204c and may further
define a separate mounting channel to couple to the control
circuitry 90. In some implementations, the second frame component
1200b may instead be snap-fit and/or press-fit into the mounting
channel 1204c.
[0226] The first frame component 1200a may include a coolant
channel 1220 that is disposed at one end of the first side 1202a to
receive the coolant pipe 1006. The assembly of the first frame
component 1200a and the second frame component 1200b may also
define a center channel 1221, which reduces the weight of the
lighting fixture 1000b, the amount of material used for
manufacture, and/or provides a thermal barrier to increase the
thermal resistance between the LED modules 410d and the control
circuitry 90 to reduce heating of the control circuitry 90.
[0227] For the lighting fixtures 1000a and 1000b, the LED modules
410a-410d are shown in FIGS. 2A-2I and 13A-13E to be disposed on
one side of the first frame component 1200a. However, it should be
appreciated that the LED modules may also be disposed on different
sides of the frame to emit radiation with a larger angular
distribution compared to lighting fixtures where the LED modules
are disposed only on one side of the frame. Said in another way,
each LED module may have a particular field of view within which
radiation is emitted. By placing LED modules on different sides of
the frame, the lighting fixture may provide radiation covering a
larger area. For example, the lighting fixture may have multiple
LED modules disposed on different sides of a frame to provide
bi-directional (e.g., interlighting), tri-directional, or
quad-directional illumination.
[0228] In some implementations, the lighting fixture may include
two LED modules disposed on opposing sides of a frame to emit
radiation in opposing directions. If the two LED modules have a
field of view of a hemisphere (i.e., the field of view is equal to
a steradians or the field of view has a 180 degree angular
distribution), the lighting fixture may provide substantially
omni-directional illumination of the plants. For example, the
lighting fixture may be hung from a ceiling in a vertical
orientation to illuminate two or more walls of plants where the
plants are grown on the vertical surfaces of the walls. In another
example, the controlled agricultural environment may include a
cylindrical wall where the plants are grown. The lighting fixture
may be positioned along a center axis of the cylindrical wall to
provide omni-directional lighting of all the plants disposed on the
cylindrical wall.
[0229] In some implementations, multi-directional emission of
radiation may be accomplished, in part, by constructing the frame
from multiple frame components. For example, FIG. 14 shows an
exemplary lighting fixture 1000c configured to provide
bi-directional lighting (interlighting). As shown, the lighting
fixture 1000c may include a first frame component 1200a with a
first exterior side 1202a-1 to support a LED module 410a-1 via a
first exterior mounting channel 1204a-1 and a second exterior side
1202a-2 opposite the first exterior side 1202a-1 to support a LED
module 410a-2 via a second exterior mounting channel 1204a-2. The
first frame component 1200a may further include a first interior
side 1202b-1 and a second interior side 1202b-2 that each support a
coolant pipe 1006 (i.e., the lighting fixture 1000c may have two
coolant pipes 1006). The first and second mounting channels 1204a-1
and 1204a-2 may be coupled together via side ribs 1218. As before,
each side rib 1218 may still form a mounting channel 1204b to
couple a second frame component 1200b to the first frame component
1200a and/or couple respective end caps 1320a and 1320b to the
first frame component 1200a.
[0230] The side ribs 1218 may further be shaped and/or dimensioned
such that the first frame component 1200a defines a cavity 1227
separating the first interior side 1202b-1 from the second interior
side 1202b-2. In some implementations, the first frame component
1200a may be split into two separate components to facilitate
assembly, in particular, the press-fit of the coolant pipes 1006 to
the first frame component 1200a. The pair of frame components may
then be coupled together using various coupling mechanisms
including, but not limited to, a screw fastener, a bolt fastener,
adhesive, a clip, and a clamp.
[0231] FIG. 14 shows the second frame component 1200b may be
inserted into the cavity 1227 and slidably coupled to the first
frame component 1200a via the rails 1226 disposed on the second
frame component 1200b that engage the mounting channels 1204b. The
second frame component 1200b, in turn, may define a cavity 1228 to
contain the control circuitry 90 via mounting channels 1229. Thus,
the control circuitry 90 may remain disposed between the coolant
pipes 1006 and, by extension, the LED modules 410a-1 and 410a-2. In
some implementations, the control circuitry 90 may be sandwiched
between the coolant pipes 1006 to reduce or, in some instances,
prevent heating of the control circuitry 90 by the LED modules
410a-1 and 410a-2.
[0232] FIG. 14 further shows the tube 1300 may contain the first
frame component 1200a, the second frame component 1200b, the LED
modules 410a-1 and 410a-2, and the control circuitry 90 as before.
It should be appreciated the dimensions of the tube 1300, the first
frame component 1200a, the second frame component 1200b, and the
coolant pipes 1006 may be adjusted to fit within the cavity 1302 of
the tube 1300.
[0233] FIGS. 16A-16C show an exemplary electrical cable assembly
1150 partially routed through an end cap 1320a in the lighting
fixture 1000a. The electrical cable assembly 1150 may generally
provide AC power supplied at a voltage ranging between 208 V to 277
V and a current ranging between 15 A and 30 A. As shown, the
electrical cable 1150 may include a drop tee connector 1153 to
facilitate connection to multiple lighting fixtures 1000a or 1000b.
The drop tee connector 1153 may include a first cable section 1152a
with a male connector 1154a, a female connector 1154b directly
disposed on the drop tee connector 1153, and a second cable section
1152b for the lighting fixture. The second cable section 1152b may
pass through the electrical feedthrough 1335 of the end cap cover
1330 and the electrical feedthrough opening 1355 of the end cap
support 1350. In some implementations, the cable section 1152b may
include one or more flag connectors 1155 for connection to the
control circuitry 90 and/or the power board 91.
[0234] In some implementations, the end cap 1320a may include a
sleeve disposed within the cavity 1302 of the tube 1300 where a
portion of the cable section 1152b passes through the sleeve. FIG.
28C shows a clamp 1156 may securely couple the cable section 1152b
to the sleeve, in part, to prevent the cable section 1152b from
being pulled out from the end cap 1320a.
[0235] In some implementations, the electrical cable assembly 1150
and the end cap 1320a may be assembled together before the end cap
1320a is installed on the frame 1004 and/or the tube 1300. Said in
another way, the electrical cable assembly 1150 and, in particular,
the cable section 1152b may be coupled to the end cap 1320a
separately before assembly with the other components of the
lighting fixtures 1000a and 1000b.
CONCLUSION
[0236] All parameters, dimensions, materials, and configurations
described herein are meant to be exemplary and the actual
parameters, dimensions, materials, and/or configurations will
depend upon the specific application or applications for which the
inventive teachings is/are used. It is to be understood that the
foregoing embodiments are presented primarily by way of example and
that, within the scope of the appended claims and equivalents
thereto, inventive embodiments may be practiced otherwise than as
specifically described and claimed. Inventive embodiments of the
present disclosure are directed to each individual feature, system,
article, material, kit, and/or method described herein.
[0237] In addition, any combination of two or more such features,
systems, articles, materials, kits, and/or methods, if such
features, systems, articles, materials, kits, and/or methods are
not mutually inconsistent, is included within the inventive scope
of the present disclosure. Other substitutions, modifications,
changes, and omissions may be made in the design, operating
conditions and arrangement of respective elements of the exemplary
implementations without departing from the scope of the present
disclosure. The use of a numerical range does not preclude
equivalents that fall outside the range that fulfill the same
function, in the same way, to produce the same result.
[0238] The above-described embodiments can be implemented in
multiple ways. For example, embodiments may be implemented using
hardware, software or a combination thereof. When implemented in
software, the software code can be executed on a suitable processor
or collection of processors, whether provided in a single computer
or distributed among multiple computers.
[0239] Further, it should be appreciated that a computer may be
embodied in any of a number of forms, such as a rack-mounted
computer, a desktop computer, a laptop computer, or a tablet
computer. Additionally, a computer may be embedded in a device not
generally regarded as a computer but with suitable processing
capabilities, including a Personal Digital Assistant (PDA), a smart
phone or any other suitable portable or fixed electronic
device.
[0240] Also, a computer may have one or more input and output
devices. These devices can be used, among other things, to present
a user interface. Examples of output devices that can be used to
provide a user interface include printers or display screens for
visual presentation of output and speakers or other sound
generating devices for audible presentation of output. Examples of
input devices that can be used for a user interface include
keyboards, and pointing devices, such as mice, touch pads, and
digitizing tablets. As another example, a computer may receive
input information through speech recognition or in other audible
format.
[0241] Such computers may be interconnected by one or more networks
in a suitable form, including a local area network or a wide area
network, such as an enterprise network, an intelligent network (IN)
or the Internet. Such networks may be based on a suitable
technology, may operate according to a suitable protocol, and may
include wireless networks, wired networks or fiber optic
networks.
[0242] The various methods or processes outlined herein may be
coded as software that is executable on one or more processors that
employ any one of a variety of operating systems or platforms.
Additionally, such software may be written using any of a number of
suitable programming languages and/or programming or scripting
tools, and also may be compiled as executable machine language code
or intermediate code that is executed on a framework or virtual
machine. Some implementations may specifically employ one or more
of a particular operating system or platform and a particular
programming language and/or scripting tool to facilitate
execution.
[0243] Also, various inventive concepts may be embodied as one or
more methods, of which at least one example has been provided. The
acts performed as part of the method may in some instances be
ordered in different ways. Accordingly, in some inventive
implementations, respective acts of a given method may be performed
in an order different than specifically illustrated, which may
include performing some acts simultaneously (even if such acts are
shown as sequential acts in illustrative embodiments).
[0244] All publications, patent applications, patents, and other
references mentioned herein are incorporated by reference in their
entirety.
[0245] All definitions, as defined and used herein, should be
understood to control over dictionary definitions, definitions in
documents incorporated by reference, and/or ordinary meanings of
the defined terms.
[0246] The indefinite articles "a" and "an," as used herein in the
specification and in the claims, unless clearly indicated to the
contrary, should be understood to mean "at least one."
[0247] The phrase "and/or," as used herein in the specification and
in the claims, should be understood to mean "either or both" of the
elements so conjoined, i.e., elements that are conjunctively
present in some cases and disjunctively present in other cases.
Multiple elements listed with "and/or" should be construed in the
same fashion, i.e., "one or more" of the elements so conjoined.
Other elements may optionally be present other than the elements
specifically identified by the "and/or" clause, whether related or
unrelated to those elements specifically identified. Thus, as a
non-limiting example, a reference to "A and/or B", when used in
conjunction with open-ended language such as "comprising" can
refer, in one embodiment, to A only (optionally including elements
other than B); in another embodiment, to B only (optionally
including elements other than A); in yet another embodiment, to
both A and B (optionally including other elements); etc.
[0248] As used herein in the specification and in the claims, "or"
should be understood to have the same meaning as "and/or" as
defined above. For example, when separating items in a list, "or"
or "and/or" shall be interpreted as being inclusive, i.e., the
inclusion of at least one, but also including more than one, of a
number or list of elements, and, optionally, additional unlisted
items. Only terms clearly indicated to the contrary, such as "only
one of" or "exactly one of," or, when used in the claims,
"consisting of," will refer to the inclusion of exactly one element
of a number or list of elements. In general, the term "or" as used
herein shall only be interpreted as indicating exclusive
alternatives (i.e. "one or the other but not both") when preceded
by terms of exclusivity, such as "either," "one of," "only one of,"
or "exactly one of." "Consisting essentially of" when used in the
claims, shall have its ordinary meaning as used in the field of
patent law.
[0249] As used herein in the specification and in the claims, the
phrase "at least one," in reference to a list of one or more
elements, should be understood to mean at least one element
selected from any one or more of the elements in the list of
elements, but not necessarily including at least one of each and
every element specifically listed within the list of elements and
not excluding any combinations of elements in the list of elements.
This definition also allows that elements may optionally be present
other than the elements specifically identified within the list of
elements to which the phrase "at least one" refers, whether related
or unrelated to those elements specifically identified. Thus, as a
non-limiting example, "at least one of A and B" (or, equivalently,
"at least one of A or B," or, equivalently "at least one of A
and/or B") can refer, in one embodiment, to at least one,
optionally including more than one, A, with no B present (and
optionally including elements other than B); in another embodiment,
to at least one, optionally including more than one, B, with no A
present (and optionally including elements other than A); in yet
another embodiment, to at least one, optionally including more than
one, A, and at least one, optionally including more than one, B
(and optionally including other elements); etc.
[0250] In the claims, as well as in the specification above, all
transitional phrases such as "comprising," "including," "carrying,"
"having," "containing," "involving," "holding," "composed of," and
the like are to be understood to be open-ended, i.e., to mean
including but not limited to. Only the transitional phrases
"consisting of" and "consisting essentially of" shall be closed or
semi-closed transitional phrases, respectively, as set forth in the
United States Patent Office Manual of Patent Examining Procedures,
Section 2111.03.
* * * * *